NZ615225A - Methods of producing biofuels, chlorophylls and carotenoids - Google Patents
Methods of producing biofuels, chlorophylls and carotenoids Download PDFInfo
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- NZ615225A NZ615225A NZ615225A NZ61522512A NZ615225A NZ 615225 A NZ615225 A NZ 615225A NZ 615225 A NZ615225 A NZ 615225A NZ 61522512 A NZ61522512 A NZ 61522512A NZ 615225 A NZ615225 A NZ 615225A
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-
- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11B—PRODUCING, e.g. BY PRESSING RAW MATERIALS OR BY EXTRACTION FROM WASTE MATERIALS, REFINING OR PRESERVING FATS, FATTY SUBSTANCES, e.g. LANOLIN, FATTY OILS OR WAXES; ESSENTIAL OILS; PERFUMES
- C11B3/00—Refining fats or fatty oils
- C11B3/10—Refining fats or fatty oils by adsorption
-
- C—CHEMISTRY; METALLURGY
- C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
- C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
- C12P7/00—Preparation of oxygen-containing organic compounds
- C12P7/64—Fats; Fatty oils; Ester-type waxes; Higher fatty acids, i.e. having at least seven carbon atoms in an unbroken chain bound to a carboxyl group; Oxidised oils or fats
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
- C10L1/00—Liquid carbonaceous fuels
- C10L1/02—Liquid carbonaceous fuels essentially based on components consisting of carbon, hydrogen, and oxygen only
- C10L1/026—Liquid carbonaceous fuels essentially based on components consisting of carbon, hydrogen, and oxygen only for compression ignition
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
- C10L1/00—Liquid carbonaceous fuels
- C10L1/04—Liquid carbonaceous fuels essentially based on blends of hydrocarbons
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
- C10L1/00—Liquid carbonaceous fuels
- C10L1/04—Liquid carbonaceous fuels essentially based on blends of hydrocarbons
- C10L1/08—Liquid carbonaceous fuels essentially based on blends of hydrocarbons for compression ignition
-
- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11B—PRODUCING, e.g. BY PRESSING RAW MATERIALS OR BY EXTRACTION FROM WASTE MATERIALS, REFINING OR PRESERVING FATS, FATTY SUBSTANCES, e.g. LANOLIN, FATTY OILS OR WAXES; ESSENTIAL OILS; PERFUMES
- C11B1/00—Production of fats or fatty oils from raw materials
- C11B1/02—Pretreatment
-
- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11B—PRODUCING, e.g. BY PRESSING RAW MATERIALS OR BY EXTRACTION FROM WASTE MATERIALS, REFINING OR PRESERVING FATS, FATTY SUBSTANCES, e.g. LANOLIN, FATTY OILS OR WAXES; ESSENTIAL OILS; PERFUMES
- C11B1/00—Production of fats or fatty oils from raw materials
- C11B1/10—Production of fats or fatty oils from raw materials by extracting
-
- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11B—PRODUCING, e.g. BY PRESSING RAW MATERIALS OR BY EXTRACTION FROM WASTE MATERIALS, REFINING OR PRESERVING FATS, FATTY SUBSTANCES, e.g. LANOLIN, FATTY OILS OR WAXES; ESSENTIAL OILS; PERFUMES
- C11B3/00—Refining fats or fatty oils
- C11B3/008—Refining fats or fatty oils by filtration, e.g. including ultra filtration, dialysis
-
- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11C—FATTY ACIDS FROM FATS, OILS OR WAXES; CANDLES; FATS, OILS OR FATTY ACIDS BY CHEMICAL MODIFICATION OF FATS, OILS, OR FATTY ACIDS OBTAINED THEREFROM
- C11C3/00—Fats, oils, or fatty acids by chemical modification of fats, oils, or fatty acids obtained therefrom
- C11C3/003—Fats, oils, or fatty acids by chemical modification of fats, oils, or fatty acids obtained therefrom by esterification of fatty acids with alcohols
-
- C—CHEMISTRY; METALLURGY
- C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
- C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
- C12P7/00—Preparation of oxygen-containing organic compounds
- C12P7/64—Fats; Fatty oils; Ester-type waxes; Higher fatty acids, i.e. having at least seven carbon atoms in an unbroken chain bound to a carboxyl group; Oxidised oils or fats
- C12P7/6436—Fatty acid esters
- C12P7/6445—Glycerides
- C12P7/6472—Glycerides containing polyunsaturated fatty acid [PUFA] residues, i.e. having two or more double bonds in their backbone
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E50/00—Technologies for the production of fuel of non-fossil origin
- Y02E50/10—Biofuels, e.g. bio-diesel
Abstract
Disclose a method of isolating chlorophylls and omega-3 rich oil from algae, comprising: a. dewatering substantially intact algal cells to make an algal biomass; b. adding a first ethanol fraction to the algal biomass in a ratio of about 1 part ethanol to about 1 part algal biomass by weight; c. separating a first substantially solid biomass fraction from a first substantially liquid fraction comprising proteins; d. combining the first substantially solid biomass fraction with a second ethanol fraction in a ratio of about 1 part ethanol to about 1 part solids by weight; e. separating a second substantially solid biomass fraction from a second substantially liquid fraction comprising polar lipids; f. combining the second substantially solid biomass fraction with a third ethanol solvent fraction in a ratio of about 1 part ethanol to about 1 part substantially solid biomass by weight; g. separating a third substantially solid biomass fraction from a third substantially liquid fraction comprising neutral lipids, including omega-3 fatty acids, carotenoids, and chlorophyll, wherein the third substantially solid biomass fraction comprises carbohydrates; and h. isolating at least one of carotenoids, chlorophyll, and omega-3 fatty acids from the third substantially liquid fraction.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims the benefit under 35 U.S.C. §120 of US. Patent Application
No. 13/149,595, filed May 31, 2011, entitled Methods of ing Biofuels, Chlorophyiis and
Carotenoids, which is a continuation~in—part of and claims the benefit of US. Application No
13/081,221, filed April 6, 2011, entitled Methods of and Systems for Isolating Nutraceutical
Products from Algae, which claims priority to US. Provisional Application No. 61/321,290,
filed April 6, 2010, entitled tion with Fractionation of Oil and Proteinaceous Material
from Oleaginous Material, and US. Provisional Application No. 61/321,286, filed April 6,
2010, entitled Extraction With Fractionation of Oil and Co-Products from Oleaginous Material,
the entire contents of which are hereby incorporated by reference herein.
FIELD OF THE INVENTION
The invention is ned with extracting and fractionating algal products,
including, but not limited to, oils and proteins. More specifically, the systems and methods
described herein utilize step extraction and fractionation with a slightly nonpolar solvent
process wet algal biomass.
BACKGROUND OF THE INVENTION
eum is a natural resource composed primarily of hydrocarbons. Extracting
petroleum oil from the earth is expensive, dangerous, and often at the expense of the
environment. Furthermore, world wide reservoirs of oil are dwindling rapidly. Costs also
accumulate due to the transportation and processing required to convert petroleum oil into
usable fuels such as gasoline and jet fuel.
Algae have gained a significant importance in recent years given their ability to
e lipids, which can be used to produce nable biofuel. This ability can be exploited
to produce renewable fuels, reduce global e change, and treat
wastewater. Algae’s
superiority as a biofuel feedstock arises from a variety of factors, including high
per-acre
productivity compared to typical terrestrial oil crop , od based ock
resources,
use of otherwise non-productive, non-arable land, utilization of
a wide variety ofwater sources
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(fresh, brackish, saline, and wastewater), production of both biofuels and valuable co—products
such as carotenoids and chlorophyll.
Several thousand species of algae have been screened and studied for lipid
production ide over the past several decades. Of these, about 300 species rich in lipid
production have been identified. The lipid composition and content vary at ent stages of
the life cycle and are ed by environmental and culture conditions. The strategies and
approaches for extraction are rather different depending on individual algal species/strains
ed because of the considerable variability in biochemical composition and the physical
properties of the algae cell wall. Conventional al extraction processes, such as extrusion,
do not work well with algae given the thickness of the cell wall and the small size (about
2 to
about 20nm) of algal cells. Furthermore, the large amounts of polar lipids in algal oil, as
compared to the typical oil red from seeds, lead to refining issues.
Upon harvesting, typical algal concentrations in cultures range from about 01-10
”/0 (w/v). This means that as much as 1000 times the amount of water
per unit weight of algae
must be removed before attempting oil extraction. Currently, existing oil extraction methods
for oleaginous materials ly require almost completely dry feed to improve the yield
quality of the oil ted. Due to the amount ofenergy required to heat the algal mass to dry
it sufficiently, the algal feed to biofuel
process is rendered uneconomical. Typically, the feed is
ed 0r flaked at high temperatures to enhance the extraction. These
steps may not work
with the existing equipment due to the single cell micrometric nature of algae.
Furthermore,
algal oil is very unstable due to the presence of double bonded long chain fatty acids. The high
temperatures used in tional extraction methods cause degradation ofthe oil, thereby
increasing the costs of such methods.
It is known in the art to extract oil from dried algal
mass by using hexane as a
solvent. This process is energy intensive. The use of heat to dry and hexane
to t
produces product of lower quality as this type of processing causes lipid and protein
ation.
Algal oil extraction can be classified into two types: disruptive or non-disruptive
methods.
Disruptive methods involve cell lies by mechanical, thermal, enzymatic or chemical
methods. Most disruptive methods result in emulsions, requiring
an expensive cleanup
process. Algal oils contain a large percentage of polar lipids and proteins which enhance the
W0 2012/138438 PCT/U52012/027537
emulsification of the neutral lipids. The fication is further stabilized by the nutrient and
salt components left in the solution. The emulsion is a complex mixture, containing neutral
lipids, polar , proteins, and other algal products, which ive refining processes to
isolate the l lipids, which are the feed that is converted into biofucl.
Non—disruptive methods provide low yields. Milking is the use of solvents or
chemicals to extract lipids from a growing algal culture. While sometimes used to extract algal
products, milking may not work with some species of algae due to solvent toxicity and cell
wall disruption. This complication makes the development of a generic
process lt.
Furthermore, the volumes of solvents ed would be astronomical due to the maximum
attainable concentration of the solvent in the medium.
Multiphase extractions would require extensive distillations, using complex solvent
es, and necessitating mechanisms for solvent recovery and recycle. This makes such
extractions impractical and uneconomical for use in algal oil technologies.
Accordingly, to overcome these deficiencies, there is a need in the art for improved
methods and systems for extraction and nating algal products, in particular algal oil,
algal proteins, and algal noids.
BRIEF SUMMARY OF THE INVENTION
Embodiments bed herein relate generally to systems and methods for
extracting lipids ofvarying polarities from an oleaginous material, including for example, an
algal biomass. In particular, embodiments described herein concern extracting lipids of
varying polarities from an algal biomass using solvents of varying polarity and/or a series of
membrane filters. In some ments, the filter is a mierofilter.
In some ments of the invention, a single solvent and
water are used to
t and fractionate components present in an oleaginous material. In other embodiments,
these components include, but are not limited to, proteins, polar , and neutral
lipids. In
still other embodiments, more than one solvent is used. In still other embodiments, a mixture
of solvents is used.
In some embodiments, the methods and s described herein
are useful for
extracting coproducts of lipids from oleaginous material. Examples of such coproducts
include, without limitation, proteinaceous material, chlorophyll, and carotenoids.
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Embodiments of the present invention allow for the aneous extraction and onation
of algal products from algal biomass in a manner that allows for the production of both fiiels
and nutritional ts.
In another embodiment of the invention, a method of isolating nutraeeuticals
products from algae is provided.
In a further embodiment of the invention, a method of isolating carotenoids and
omega-3 rich oil from algae includes dewatering substantially intact algal cells to make an algal
biomass and adding a first ethanol fraction to the algal biomass in a ratio of about 1 part
ethanol to about 1 part algal biomass by weight. The method also includes separating
a first
ntially solid biomass fraction from a first substantially liquid fraction comprising
proteins and combining the first ntially solid biomass fraction with a second ethanol
fraction in a ratio of about 1 part ethanol to about 1 part solids by . The method further
includes separating a second substantially solid biomass fraction from
a second substantially
liquid fraction comprising polar lipids and combining the second substantially solid biomass
fraction with a third ethanol solvent fraction in a ratio of about 1 part ethanol to about
1 part
substantially solid biomass by . The method also includes separating a third
substantially solid biomass fraction from a third substantially liquid fraction comprising neutral
lipids, wherein the third substantially solid biomass fraction comprises carbohydrates and
separating the neutral lipids into carotenoids and omega-3 rich oil.
In yet r embodiment of the invention, the method also includes isolating
carotenoids, omega—3 rich oil, carbohydrates and polar lipids; isolating the polar lipids from
components that are not polar lipid ents; and/or isolating carotenoids from non—
carotenoid components.
In still a further embodiment of the invention, the method also includes
processing
the polar lipids into at least one of lubricants, detergents, and food additives.
[0020} In another ment of the ion, at least
one of the first, second, and third
solvent sets comprises an alcohol. ally, the alcohol is ethanol.
Embodiments ofthe present in invention include a method of isolating chlorophylls
and omega-3 rich oil from algae, comprising dewatering substantially intact
algal cells
ded in a fluid medium to generate an algal biomass; extracting a substantially liquid
fraction comprising neutral lipids, carotenoids, and chlorophylls from the algal
biomass, the
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l lipids including 3 fatty acids; and separating the carotenoids and chlorophylls
from the neutral lipids. 1n some embodiments, the separating is carried out by at least one of
adsorption and membrane diafiltration.
In other embodiments, the methods further comprise esterifying the neutral lipids
with a catalyst in the presence of an alcohol, and separating a water soluble on comprising
glycerin from a water insoluble fraction comprising fuel esters. In still other embodiments, the
separating is carried out by adsorption with an adsorbent material. In still others, the separating
is carried out by adsorption with a clay. In some embodiments, the clay is selected from the
following group consisting of bleaching clay, bentonite, and fuller’s earth.
Further embodiments of the invention include a method of isolating chlorophylls
and omega-3 rich oil from algae, comprising dewatering substantially intact algal cells
to make
an algal biomass; adding a first ethanol fraction to the algal s in
a ratio of about 1 part
ethanol to about 1 part algal biomass by weight; separating a first ntially solid s
fraction from a first substantially liquid fraction comprising proteins; combining the first
substantially solid s fraction with a second ethanol fraction in a ratio of about 1 part
ethanol to about 1 part solids by weight; separating a second substantially solid biomass
fraction from a second ntially liquid fraction comprising polar lipids; combining the
second substantially solid biomass fraction with a third ethanol solvent fraction in
a ratio of
about 1 part ethanol to about 1 part substantially solid biomass by ; separating
a third
substantially solid biomass fraction from a third substantially liquid fraction sing neutral
lipids, including omega-3 fatty acids, carotenoids, and chlorophyll, wherein the third
ntially solid biomass fraction comprises carbohydrates; and isolating at least one of
carotenoids, chlorophyll, and 3 fatty acids from the third substantially liquid fraction.
In some embodiments of the , at least one of the first, second, and third solvent
sets
comprises an ethanol. In others, at least one of the first, second, and third solvent sets
comprises an alcohol.
In yet other ments, the method r comprises esterifying the
neutral
lipids with a catalyst in the presence of an alcohol, and separating a water soluble fraction
comprising glycerin from a water insoluble fraction comprising fuel esters. In still other
embodiments, the method further comprises distilling the fuel esters under vacuum to obtain a
C16 or shorter fuel ester fraction, a C16 or longer fuel ester fraction, and
a e comprising
omega—3 fatty acids. Some embodiments flirther comprise deoxygenating the C16 or shorter
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fuel ester fraction to obtain a jet fuel blend stock and/or the C16 or longer fuel fraction
obtain a diesel blend stock. In still other embodiments, the isolating is carried out by
adsorption with an ent material. In still other embodiments, the isolating is carried out
by adsorption with a clay. In some embodiments, the clay is selected from the following
group
consisting of bleaching clay, bentonite, and fuller’s earth.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. IA is a rt of steps ed in a method according to an exemplary
embodiment of the present disclosure.
is a schematic diagram of an exemplary embodiment of
a dewatering
process according to the present disclosure.
is a schematic diagram of an exemplary embodiment of
an extraction system
according to the present disclosure.
is a comparative graph showing Sohxlet extraction of freeze dried algae
biomass using an array of solvents encompassing the complete polarity
range showing
maximum non-disruptive algae oil extraction efficiency and the effect of polarity
on the polar
and non—polar lipids extraction.
&B are graphic representations showing neutral lipids (A) Purity and (B)
Recovery in the two step solvent tion process using methanol and eum ether at
three different temperatures.
&B are graphs showing neutral lipids (A) Purity and (B) Recovery in
two step solvent extraction process using
aqueous methanol and petroleum ether at three
different temperatures.
is a graph g lipid
recovery in the two step solvent extraction s
using aqueous ol and petroleum other at three different temperatures.
is a graph showing the effect of solvents to solid biomass ratio
on lipid
recovery.
is a graph showing the efficacy of different
aqueous extraction solutions in a
single step extraction ry of aqueous methanol on dry biomass.
PCT/U82012/027537
is a graph g the effect of multiple step methanol extractions
on the
cumulative total lipid yield and the neutral lipids purity.
is a graph g the cumulative
recovery of lipids using wet biomass and
ethanol.
is a graph showing a comparison of the extraction times of the ave
assisted extraction and conventional extraction systems.
A is a flowchart of steps involved in a method according to
an exemplary
embodiment ofthe t disclosure which incorporates a step of n extraction. All of
the units in A are in pounds.
B is a flowchart of steps involved in an exemplary extraction
process
according to the present disclosure.
is a flowchart and mass balance diagram describing
one ofthe
embodiments ofthe present invention wherein 1000 lbs. of algal s
was processed
through extraction and onation in order to separate neutral lipids, polar lipids, and protein
from the algal biomass.
is a flowchart describing one of the embodiments of the
present ion
wherein an algal mass can be processed to form various products.
is a flowchart bing one of the embodiments of the
present invention
wherein algae neutral lipids are processed to form various products.
is a flowchart describing one of the embodiments of the
present invention
wherein algae neutral lipids are processed to form fuel products.
is a flowchart describing one of the embodiments of the
present invention
n algae proteins are selectively extracted from a freshwater algal biomass.
is a flowchart describing one of the embodiments of the
present invention
wherein algae proteins are ively extracted from a ter algal biomass.
is a flowchart describing one of the embodiments of the
present invention
wherein a selected algae n is extracted from a saltwater
or freshwater algal biomass.
is a flowchart describing one of the embodiments of the
present invention
wherein a selected algae protein is extracted from a saltwater
or freshwater algal biomass.
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is a photograph showing Scenedescemus
Sp. cells before and after
extraction using the methods described herein. The cells are substantially intact both before
and after extraction.
A is a flowchart of steps involved in an method of chlorophyll extraction.
B is a schematic diagram of an exemplary embodiment of chlorophyll
extraction of the present disclosure.
DETAILED DESCRIPTION
Definitions
The term “conduit” or any variation thereof, as used herein, includes
any structure
h which a fluid may be conveyed. Non—limiting examples of conduit include pipes,
, channels, or other enclosed structures.
The term “reservoir” or any variation thereof, as used , includes
any body
structure capable of retaining fluid. Non-limiting examples of reservoirs include ponds, tanks,
lakes, tubs, or other similar structures.
The term “about” or ximately,” as used herein,
are defined as being close to
as tood by one of ry skill in the art, and in
one non-limiting embodiment the terms
are defined to be within 10%, preferably within 5%,
more preferably within 1%, and most
preferably within 0.5%.
The terms “inhibiting” or “reducing” or
any variation of these terms, as used herein
includes any measurable decrease or complete inhibition to achieve
a desired result.
The term “effective,” as used herein, means adequate to lish
a desired,
expected, or intended .
The use of the word “a” or “an” when used in conjunction with the
term
“comprising” herein may mean “one,” but it is also consistent with the meaning of “one
“
more, at least one,” and “one or more than one.”
The term “or” as used herein, means “and/or” unless itly indicated
to refer to
alternatives only or the atives are mutually exclusive, although the
disclosure supports a
definition that refers to only alternatives and “and/or.”
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The use of the term “wet” as used herein, is used to mean containing about 50% to
about 99.9% water t. Water content may be located either intracellularly or
extracelluarly.
The use of the term “solvent set” as used herein, is used to mean composition
comprising one or more solvents. These solvents can be amphipathic (also known as
amphiphilic or slightly nonpolar), hilic, or hydrophobic. In some ment, thcsc
solvents are water miscible and in others, they are ible in water. Non—limiting example
of solvents that may be used to practice the methods of the instant invention include methanol,
ethanol, isopropanol, acetone, ethyl acetate, and acetonitrile, alkanes (hexane, pentane, heptane,
octane), esters (ethyl acetate, butyl acetate), ketones (methyl ethyl ketone (MEK), methyl
isobutyl ketone (MIBK)), ics (toluene, e, cyclohexane, tetrahydrofuran),
haloalkanes (chloroform, trichloroethylene), ethers (diethyl ether), and mixtures (diesel, jet
fuel, gasoline).
The term “oil” as used herein es compositions containing neutral lipids and
polar lipids. The terms “algae oil” and “algal oil” as used herein are used interchangeably.
The term “diffusate” or “permeate" as used herein
may refer to al that has
passed through a separation device, including, but not limited to a filter or membrane.
The term “retentate” as used herein
may refer to material that remains after the
diffusate has passed through a separation device.
As used herein, the words “comprising” (and
any form of comprising, such as
“comprise” and “comprises”), “having” (and any form of having, such as “have” and “has”),
“including” (and any form of including, such as “includes” and “include”), or “containing”
(and any form of ning, such as “contains” and in”) are inclusive or nded and
do not exclude additional, unrecited elements or method
steps.
The term “polar ” or any variation thereof, as used herein, includes, but
is not
limited to, phospholipids and glycolipids.
The term “neutral lipids” or any variation thereof, as used , includes, but
not limited to, triglycerides, diglycerides, monoglycerides, carotenoids,
waxes, sterols.
The term “solid phase” as used herein refers to a collection of material that is
generally more solid than not, and is not intended to mean that all of the material in the phase is
solid. Thus, a phase having a substantial amount of solids, while retaining some liquids, is
encompassed within the meaning of that term. Meanwhile, the term “liquid phase”, as used
herein, refers to a collection of material that is generally more liquid than not, and such
tion may include solid materials.
The term “biodiesel” as used herein refers to methyl or ethyl esters of fatty acids
derived from algae.
The term eeutical” as used herein refers to a food product that provides health
and/or medical benefits. Non-limiting es include carotenoids, carotenes, xanthophylls
such as zeaxanthin, astaxanthin, and lutein.
The term “biofuel” as used herein refers to fuel derived from biological
source.
Non-limiting examples include biodiesel, jet fuel, diesel, jet fuel blend stock and diesel blend
stock.
The term “impurities”, when used in connection with polar lipids,
as used herein,
refers to all components other than the products of interest that are eoextracted
or have the
same properties as the product of interest.
The term “lubricants”, when used in connection with polar ,
as used herein
refers to hydrotreated algal lipids such as C16-C20 alkanes.
The term “detergents”, when used in tion with polar lipids,
as used herein
refers to glycolipids, phospholipids and derivatives thereof.
The term “food additives”, when used in connection with polar lipids,
as used
herein refers to soy lecithin substitutes or phospholipids derived from algae.
The term lycerin ” as used herein refers to
any impurity that separates
with the glycerin fraction. A further clean
up step will remove most of what is present in order
to produce pharmaceutical grade glycerin.
The term “unsaturated fatty acids” as used herein refers to fatty acids with
at least
one double carbon bond. Non-limiting examples ofunsaturated fatty acids include palmitoleie
acid, margaric acid, stearic acid, oleie acid, octadeeenoic acid, ic acid, gamma-linoleic
acid, alpha linoleic acid, arachidic acid, eicosenoic acid, homogamma linoleic acid, arachidonie
acid, penenoic acid, behenic, doeosadienoic acid, heneieosapentaenoic, tetraenoie
acid. Fatty acids having 20 or more carbon atoms in the backbone are generally referred to as
PCT/U52012/027537
“long chain fatty acids”. The fatty acids having 19 or fewer carbon atoms in the backbone are
generally ed to as “short chain fatty acids”.
rated long chain fatty acids include, but are not limited to, omega-3 fatty
acids, omega-6 fatty acids, and omega-9 fatty acids. The term —3 fatty acids” as used
herein refers to, but is not d to the fatty acids listed in Table 1.
"{£135"Z'iiléiél'i‘i"iii’i7""éi'é'c'iééifiéfiéié'éaéi"""""" """""3:
The term “jet fuel blend stock” as used herein refers to alkanes with the carbon
chain lengths appropriate for use as jet fuels.
The term “diesel blend stock” as used herein refers to alkanes with the carbon
chain
lengths appropriate for use as diesel.
The term “animal feed” as used herein refers to algae-derived substances that
can be
consumed and used to provide nutritional support for an animal.
The term “human food” as used herein refers to algae—derived substances that
be consumed to provide nutritional support for people. Algae-derived human food products
can contain essential nutrients, such as carbohydrates, fats, proteins, vitamins,
or minerals.
The term “bioremediation” as used herein refers to use of algal growth to
remove
pollutants, such as, but not limited to, nitrates, ates, and heavy metals, from industrial
wastewater or municipal wastewater.
The term “wastewater” as used herein refers to industrial wastewater or municipal
wastewater that contain a variety of contaminants or pollutants, including, but not limited to
nitrates, phosphates, and heavy .
The term “enriched”, as used herein, shall mean about 50% or greater t.
The term “substantially”, as used herein, shall mean mostly.
The term lin proteins” as used herein refers to salt soluble proteins.
The term “albumin proteins” as used herein refers to water soluble proteins.
The term “glutelin proteins” as used herein refers to alkali soluble proteins.
The term “prolamin proteins” as used herein refers to alcohol soluble proteins.
Non-limiting examples ofprolamin ns are gliadin, zein, hordein, avenin.
The term “algal culture” as used herein refers to algal cells in culture medium.
The term “algal biomass” as used herein refers to an at least lly dewatered
algal culture.
The term “dewatered” as used herein refers to the l of at least
some water.
The term “algal paste” as used herein refers to a partially dewatered algal culture
having fluid properties that allow it to flow. Generally an algal paste has a water content of
about 90%.
The term “algal cake” as used herein refers to a partially dewatered algal culture
that lacks the fluid properties of an algal paste and tends to clump. Generally an algal cake has
a water content of about 60% or less.
Saltwater algal cells include, but are not limited to, marine and brackish algal
species. Saltwater algal cells are found in nature in bodies ofwater such
as, but not limited to,
seas, oceans, and estuaries. Non-limiting examples of ter algal s include
Nannochloropsz’s sp., Dumzlz’ella Sp.
PCT/U82012/027537
Freshwater algal cells are found in nature in bodies of water such as, but not limited
to, lakes and ponds. Non-limiting examples of freshwater algal species include Scendescemus
5p. , Haemotococcus Sp.
Non—limiting examples ofmicroalgae that can be used with the s of the
invention are members of one of the following divisions: Chlorophyta, Cyanophyta
(Cyanobaeteria), and Heterokontophyta. In certain embodiments, the microalgae used with the
methods of the ion are members of one of the following classes: Bacillarz’ophyceae,
Eustz‘gmatophyceae, and Chrysophyceae. In certain embodiments, the microalgae used with the
methods ofthe invention are members of one of the following
: Nannochloropsz’s,
Chlorella, Dunalz‘ella, Scenedesmus, Selenastrum, Oscillatoria, Phormz'a’z‘um, Spirulz'na,
Amphora, and Ochromonas.
miting examples of microalgae species that can be used with the s of
the t invention include: Achnanrhes orientalz's, llum
$1717., mra hya/z'ne,
Amp/mm j‘brmz‘s, Amp/mm coffézj‘brmis var. Zinea, Amphora cofl‘eiformis var. punctata,
Amphora cofi’eiformis var. taylori, m cofi’ez'formis var. , Amphora delicatl'ssz'ma,
Amp/10m delicarz‘ssz’ma var. . capitata, Amphora S11, Anabaena, Ankz'stmdesmus,
Ankz‘strodesmusfalcatus, Boekelovz’a hooglandz'i, Borodinella Sp., Botryococcus braum'z',
Bonyococcus sudetz'cus, Bracteococcus minor, Bracteococcus medionucleatus, Carterz'a,
Chaetoceros gracilis, Chaetoceros muellerz‘, Chaetoceros muellerz' var. subsalsum,
Chaetoceros sp., Chlamydomas perigranulata, Chlorella anitrata, Chlorella tica,
Chlorella aureovz'ridz's, Chlorella Candida, Chlorella capsulate, Chlorella ate, Chlorella
ellipsoidea, Chlorella emersanii, Chlorellafusca, Chlorellafusca var. vacuolata, Chlorella
glucotropha, Chlorella infitsz‘onum, lla infiisz‘onum var. actophz'la, Chlorella infirsz'onum
var. auxenophila, Chlorella kessleri, Chlorella lobaphora, Chlorella luteoviridis, Chlorella
luteovz‘rz'dis var. aureovz‘rz’dz‘s, Chlore/la luteovz'ridz‘s var. lutescens, Chlorella miniata,
Chlorella minutissz'ma, Chlorella mutabilis, Chlorella nocturna, Chlorella ovalis, Chlorella
paiva, Chlorella plwtophz'la, Chlorella pringsheimii, Chlarella protothecoz‘des, Chlorella
protothecoz‘a’es var. ola, Chlorella regularz's, Chlorella regularis var. minima, lla
regularis var. umbrz’cata, Chlorella reisz'gliz‘, Chlorella saccharophz‘la, lla rophz'la
var. ellipsoidea, Chlorella salina, Chlorella simplex, Chlorella 'm‘ana, Chlorella
Chlorella sphaerica, Chlorella stigmatophora, Chlorella vannz‘e/lz‘z', Chlorella vulgarz's,
Chlorella vulgarisfo. terria, Chlorella vulgaris var. autotrophz‘ca, Chlorella vulgaris
var.
W0 2012/138438 2012/027537
vz'rz‘dz'S, Chlorella vulgaris var. vulgaris, Chlorella vulgaris var. vulgarisfo. tertia, Chlorella
iS var. vulgarisfo. viridz‘s, Chlorella xanthella, Chlorella zofingierzSiS, Chlorella
xz'oz'des, Chlorella vulgariS, Chlorococcum infusionum, Chlorococcum Sp,
Chlorogorzz'um, Chroomonas Sp, CthSOSphaera Sp, Cricosphaera Sp, Crwthecodz’m’um
colmz'z', Cryptomonas Sp, Cyclotella cryptica, Cyclolella menegkim'ana, Cyclotella Sp,
Dzmalz‘ella Sp, Dzmalz'ella bardawil, Dunaliella bz'oculata, Dunaliella ate, Dunaliella
maritime, Dunalz’ella mimlta, Dunalz'elia parva, Dzmalz’ella pez‘rcez‘, Dunalz’ella primolecta,
ella salina, Dzmaliella terricola, Dzmalz'ella terliolecta, Dunalz'ella viridis, Dunalz’ella
terliolecta, Eremosphaera viridz's, Eremasphaera Sp, Ellipsoidon Sp, Euglena Spp, z'a
Sp, Fragilarz'a crotonensz’s, Fragilarz’a Sp, Gleocapsa Sp, Gloeothamniorz Sp, Haematococcus
pluvz'alz'S, Hymenomonas Sp, [sochrysz's ajj‘. galbana, [sochrysz's galbana, Lepocinclis,
filicractinium, Alicractiniwn, Alonoraphz’dium minutum, phidium Sp, Nannochloris Sp,
Nannochloropsis salina, hlampsz‘s Sp, Navicula accepzata, Navicula biskamerae,
Navicula pseudotenelloz‘des, Navz'cula culosa, Navicula saprophila, Navicula
chloris Sp, Nephroselmis Sp, Nz'tschia communis, Nitzschz'a alexandrz‘na, Nitzschia
closterz'um, Nitzschia communis, Nitzschz‘a dissipata, Nitzschz‘afiustulum, Nitzschia
chz’ana, Nitzschz’a inconspicua, Nitzschz'a intermedia, Nitzschz‘a microcephala, Nitzschz'a
pusilla, Nitzschia a elliptica, Nitzschia pusz‘lla monoenSZS, Nitzschia quadrangular,
Nitzschz‘a Sp, Ochromonas Sp, OocyStz'S parva, Oocystis pusz'lla, Oocystis
Sp, Oscillatorz'a
limaetz’ca, Oscz'llatorz'a Sp, Oscillatoria subbrevis, Parachlorella kesslerz', Pascheria
hila, a Sp, Phaeodacgzlum tricomutum, Phagus, Phormz’dium, Platymonas Sp,
chrysis ae, Pleurochrysis dentate, Pleurochljzsz‘s Sp, Protoz‘heca wickel‘hamii,
Prototheca Stagnora, Prototheca portorz'censz's, Protorheca morzformis, Prototheca zap/ii,
Pseudochlorella aquatica, Pyramimonas Sp, erobotrys, Rhodococcus
opacus, Sarcz'noz’a’
phyte, Scenedesmus armatuS, Schizochytrium, yra, Spirulina platenSis,
Stz'chococcus Sp, Synechococcus Sp, Synechocystz’sf, TageteS erecta, T
ageteS patula,
Tetraedron, Tetraselmz‘s Sp, Tetraselmis suecz’ca, Thalassz'osz'ra weissflogz‘z’, and Viridz'ella
fridericz'ana.
In other embodiments, the s can be plant material, including but not limited
to soy, corn, palm, camelina, jatropha, canola, coconut, peanut, safflower, seed, linseed,
sunflower, rice bran, and olive.
Systems and methods for extracting lipids and coproducts (e.g., proteins) of varying
polarity from a wet oleaginous material, including for e, an algal biomass, are disclosed.
In ular, the methods and systems described herein concern the ability to both extract and
fractionate the algae components by doing sequential extractions with a hydrophilic
solvent/water mixture that becomes progressively less polar , water in t/water ratio is
progressively reduced as one proceed from one extraction step to the next). In other words, the
interstitial solvent in the algae (75% of its weight) is initially water and is replaced by the
slightly nonpolar solvent gradually to the azeotrope of the organic solvent. This s in the
extraction of components soluble at the polarity developed at each step, thereby leading to
simultaneous fractionation of the extracted components. Extraction ofproteinaceous
byproducts by acid ng and/or alkaline extraction is also disclosed.
In some embodiments of the invention, a single solvent and water are used to
t and fractionate components present in an oleaginous material. In other embodiments, a
solvent set and water are used to extract and fractionate components present in an oleaginous
material. In some embodiments the oleaginous material is wet. In other embodiments, the
oleaginous material is algae.
Polar lipid recovery depends mainly on its ionic , water solubility, and
location (intracellular, extracellular or membrane bound). es ofpolar lipids include, but
are not d to, phospholipids and ipids. Strategies that can be used to te and
purify polar lipids can roughly be divided into batch or continuous modes. Examples ofbatch
modes include precipitation (pH, organic solvent), t extraction and crystallization.
Examples of continuous modes include centrifuging, adsorption, foam separation and
precipitation, and membrane technologies (tangential flow filtration, diafiltration and
precipitation, ultra filtration).
Other objects, features and advantages of the present invention will become
apparent from the ing detailed description. It should be understood, however, that the
detailed description and the examples, while indicating specific embodiments of the invention,
are given by way of ration only. onally, it is plated that changes and
modifications within the range and scope of the invention will become apparent to those skilled
in the art from this detailed description.
Surprisingly, the proposed non-disruptive extraction process results in over 90%
recovery. The small amount of polar lipids in the remaining biomass enhances its value when
PCT/USZOIZ/027537
the remaining biomass is used for feed. This is due, at least in part, to the high long chain
unsaturated fatty acid content of the biomass. In on, ethanol extracts can further be
directly transesterified. Furthermore, unlike the existing tional methods, the s
and systems described herein are generic for
any algae, and enable recovery of a icant
portion of the le components, ing polar lipids, in the algae by the use of a water
miscible organic solvent gradient.
The neutral lipid fraction obtained by the use of the
present invention possesses a
low metal t, thereby enhancing stability of the lipid fraction, and ng
subsequent
processing steps. Metals tend to make neutral lipids unstable due to their ability to catalyze
oxidation. Furthermore, metals inhibit hydrotreating sts, necessitating their removal
before a neutral lipid mixture can be refined. The systems and methods disclosed herein
allow
for the extraction of metals in the protein and/or the polar lipid fractions. This is advantageous
because proteins and polar lipids are not highly affected by metal
exposure, and in some cases
are actually stabilized by .
The systems and methods disclosed herein can start with wet biomass, reducing
drying and dewaterin g costs. Compared to conventional extraction processes, the disclosed
extraction and fractionation processes should have relatively low operating
costs due to the
moderate temperature and pressure conditions, along with the solvent recycle.
Furthermore,
conventional tion processes are cost prohibitive and cannot meet the demand
ofthe
market.
Another aspect of the systems and methods bed herein is the ability
accomplish preliminary refining, which is the separation of polar lipids from neutral lipids
during the extraction process. The differences between algal oil used in exemplary
embodiments and vegetable oils used in previous embodiments e the
percentage of
individual classes of lipids. An exemplary algal crude oil composition is
compared with
vegetable oil shown in Table 2 below:
Table 2
Algal Crude Oil (w/W) Vegetable Oil (W/w)
Neutral lipids 30-90% 90-98%
PCT/U52012/027537
Phospholipids 10-40%
Glycolipids 10-40%
Free fatty acids l-10%
Pigments
Degumming (physical and/or chemical) of vegetable oil is done in order to remove
polar lipids (e.g., glycolipids and phospholipids). Vegetable oil that has been chemically
degummed retains a significant quantity of neutral lipid. This neutral lipid fraction is further
removed from the degummed material using solvent extraction or supercritical/subcritieal fluid
extraction or membrane technology. In st, separation of the neutral lipids from an
oleaginous algal s is far more lt than from a vegetable oil feedstock due to the
presence of large quantities of polar lipids typically found in algal oil (see Table 2). This is
because the larger percentage of polar lipids present in algal oil enhances the fication of
the neutral lipids. The emulsification is further stabilized by the nutrient and salt
components
left in the solution. The presence of polar lipids, along with metals, results in processing
difficulties for separation and utilization of neutral lipids. However, because polar lipids have
an existing market, their recovery would add significant value to the
use of algal oil to generate
fuels.
Polar lipids are tants by nature due to their lar structure and have
huge existing market. Many of the existing technologies for ing polar lipids are raw
material or cost prohibitive. Alternative feedstocks for glycolipids and phospholipids are
mainly algae oil, oat oil, wheat germ oil and vegetable oil. Algae oil typically contains about
—85 % (w/w) polar lipids depending on the species, physiological status of the cell,
culture
conditions, time of t, and the solvent utilized for extraction. Further, the glycerol
backbone of each polar lipid has two fatty acid
groups attached instead of three in the neutral
lipid triacylglycerol. Transesterification of polar lipids may yield only two-thirds ofthe end
product, z’.e., esterified fatty acids, as compared to that of neutral lipids, on a per mass basis.
Hence, removal and recovery of the polar lipids would not only be highly beneficial in
W0 2012/138438 PCT/U52012/027537
producing high quality biofuels or triglycerides from algae, but also te value-added co-
products glycolipids and olipids, which in turn can offset the cost associated with algae-
based biofuel production. The ability to easily recover and fractionate the various oil and
products produced by algae is advantageous to the economic success of the algae oil process.
A r aspect of the s and systems described herein is the ability to
extract
proteins from an oleaginous material, such as algal biomass. The s disclosed herein of
extraction of proteinaceous material from algal biomass comprise a flexible and highly
customizable s of extraction and fractionation. For example, in some embodiments,
extraction and fractionation occur in a single step, thereby ing a highly efficient
process.
Proteins sourced from such biomass are useful for animal feeds, food ingredients and rial
products. For example, such proteins are useful in applications such as fibers, adhesives,
coatings, ceramics, inks, cosmetics, textiles, chewing gum, and biodegradable plastics.
Another aspect of the methods and systems described herein involves varying the
ratio of algal biomass to t based on the components to be extracted. In one embodiment,
an algal biomass is mixed with an equal weight of t. In another embodiment, an algal
biomass is mixed with a lesser weight of solvent. In yet r embodiment, an algal biomass
is mixed with a greater weight of solvent. In some embodiments, the amount of solvent mixed
with an algal biomass is calculated based on the solvent to be used and the desired polarity
the algal biomass/solvent mixture. In still other embodiments, the algal mass is extracted in
several steps. In an exemplary embodiment, an algal biomass is sequentially extracted, first
with about 50-60% of its weight with a slightly nonpolar, water miscible solvent. Second, the
remaining algal solids are extracted using about 70% of the ’ weight in solvent. A third
extraction is then performed using about 90% ofthe solid’s weight in solvent. Having been
informed of these aspects of the invention, one of skill in the art would be able to
use ent
solvents of different polarities by adjusting the ratios of algal biomass and/or solid residuals
the d polarity in order to selectively extract algal products.
For example, in preferred embodiment, the solvent used is ethanol. Components
may be selectively isolated by varying the ratio of solvent. Proteins can be extracted from an
algal biomass with about 50% ethanol, polar lipids with about 80% ethanol, and neutral lipids
with about 95% or greater ethanol. anol were to be used, the solvent concentration to
extract proteins from an algal biomass would be about 70%. Polar lipids would require about
90% methanol, and neutral lipids would e about 100% methanol.
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Embodiments ofthe systems and methods described herein exhibit surprising and
unexpected s. First of all, the ry/extraction s can be done on a wet biomass.
This is a major economic advantage as exemplary embodiments avoid the
use of large amounts
of energy ed to dry and t the cells. Extraction of neutral lipids from a dry algal
biomass is far more effective using the systems and methods of the
present invention. The
yields obtained from the disclosed processes are significantly higher and purer than those
obtained by conventional extractions. This is because conventional extraction frequently
results in emulsions, rendering component separations extremely difficult.
ary embodiments may be applied to any algae or non—algae oleaginous
material. Exemplary embodiments may use
any water-miscible slightly nonpolar solvent,
including, but not limited to, methanol, ethanol, panol, acetone, ethyl acetate, and
acetonitrile. Specific embodiments may use a green renewable solvent, such as ethanol. The
alcohol solvents tested resulted in higher yield and purity of isolated l lipids.
Ethanol is
relatively economical to purchase as compared to other solvents disclosed herein. In some
ary embodiments, extraction and fractionation can be performed in one step followed by
membrane-based purification ifneeded. The resulting biomass is almost devoid of
water and
can be tely dried with lesser energy than an aqueous algae slurry.
In some exemplary embodiments, the solvent used to extract is ethanol. Other
embodiments include, but are not limited to, cyclohexane, eum ether,
pentane, hexane,
e, diethyl ether, toluene, ethyl acetate, chloroform, dicholoromethane, acetone,
acetonitrile, isopropanol, and methanol. In some embodiments, the same solvent is used in
tial extraction steps. In other embodiments, different solvents are used in each
extraction step. In still other embodiments, two or more solvents
are mixed and used in one or
more extraction steps.
In some embodiments of the methods described ,
a mixture oftwo or more
ts used in any of the extraction steps includes at least
one hydrophilic solvent and at least
one hydrophobic solvent. When using such a mixture, the hydrophilic solvent
ts the
material from the biomass via diffusion. Meanwhile, a relatively small amount of hydrophobic
solvent is used in combination and is involved in a liquid—liquid separation such that
material of interest is concentrated in the small amount of hydrophobic solvent. The
different solvents then form a two-layer system, which can be separated using techniques
known in the art. In such an implementation, the hydrophobic solvent
can be any one or more
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of an alkane, an ester, a ketone, an aromatic, a haloalkane, an ether,
or a commercial mixture
(e.g., diesel, jet fuel, gasoline).
In some embodiments, the extraction
processes described herein incorporate pH
ion in one or more steps. Such pH excursion is useful for isolating proteinaceous
material. In some embodiments, the pH of the extraction
process is acid (e. g., less than about
). In some embodiments, the pH of the extraction
process is alkaline (e.g., greater than about
).
The use of hexane in conventional extraction procedures contaminates algal
s such that coproducts may not be used in food products. Embodiments ofthe
present
invention are or to those known in the art as they require the
use of far less energy and
render products suitable for use as fuels as well as foodstuffs and nutrient supplements.
It is contemplated that any ment discussed in this specification
can be
implemented with respect to any method or system of the invention, and vice versa.
rmore, systems of the invention can be used to achieve s of the invention.
DESCRIPTION OF ARY EMBODIMENTS
For solvent extraction of oil from algae the best case scenario is
a solvent which
selectively extracts triacylglycerols (TAG) and leaving all polar lipids and non—TAG neutral
lipids such as waxes, sterols in the algal cell with high recoveries. The second option would be
selectively extract polar lipids and then extract purer neutral lipids devoid of polar lipids,
resulting in high recovery. The last option would be to extract all the lipids and e
very
high ry in one or two steps.
Referring now to FIG. IA, a flowchart 100 provides an overview of the steps
involved in exemplary ments ofmethods used in the fractionation and
purification of
lipids from an algae-containing s. In a first step 110, algal cells are harvested. In a
subsequent step 120, water is removed from algal cells to yield a 10-25% solid s. In
step 130, a solvent-based extraction is performed on the biomass and the fractions are
collected. In some embodiments, step 130 will also incorporate pH-based extraction and
fraction collection. Finally, a solid/liquid phase separation, including, but not limited to
techniques such as filtration, decanting, and centrifugation, may be performed in a step 140 to
in order to separate out smaller lipid components.
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The algae biomass when harvested in step 110 typically consists of about 1-5 g/L of
total solids. The biomass can be partially dewatered in step 120 using techniques including,
but not limited to, dissolved air floatation, membrane filtration, flocculation, sedimentation,
filter pressing, decantation or centrifiigation. Dewatering is the removal of some, most, or all
of the water from a solid or semisolid substance. Embodiments of the
present ion utilize
dewatering techniques to remove water from a harvested algal biomass. Dewatering can be
carried out using any one of or a combination of
any of the methods described herein, as well
as by any other s known to one of skill in the art.
The dewatered algae biomass resulting from step 120 typically consists of about 10—
% solids. This s can then be extracted with water miscible slightly nonpolar solvents
(e.g. , alcohols), in a multistage countercurrent solvent extraction s ating the
fractions at each stage. This type of process can reduce both capital and operating
In some embodiments, the biomass also undergoes acid and/or alkaline extraction
to fractionate
n material.
[0122} In some embodiments, dewatering of an algal biomass
can be carried out by treating
the harvested algal biomass with a solvent such as ethanol. The algal biomass is then allowed
to settle out of on and the liquids may then be removed by methods such
as, but not
d to, siphoning. This novel method of dewatering has lower capital and opcrating costs
than known methods, enables solvent recycling, reduces the cost of drying the biomass,
and has
the added benefit of sing the polarity of the algal biomass prior to beginning
tion
and/or separation of algal components. In fact, it is theorized that the solvent—based
sedimentation processes described herein are effective, in part, due to the fact that organic
ts reduce or neutralize the negative charge on the algae surface. In some embodiments
ofthe invention, ring methods are combined in order to
remove even more water. In
some embodiments, the addition of solvent during the dewatering
process begins the process of
tion.
shows an illustrative implementation of a dewatering
process 300. An
algal culture 310 having a final dry weight of about 1 g/L to about 10 g/L (226., 0.1-l% w/w) is
subjected to a water separation process 320. Process 320 can include centrifugation, decanting,
settling, or filtration. In one embodiment, a sintered metal tube filter is used to
separate the
algal biomass from the water of the culture. When using such a filter, the recovered water 330
is ed directed to other algae cultures. Meanwhile, the algal biomass recovered has been
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concentrated to an “algae paste” with a algae density as high as about 200 g/L (226., 10-20%
w/w). This trated algae paste is then treated with a solvent 340 in a solvent-based
sedimentation process 350.
Sedimentation process 350 involves adding solvent 340 to the algae paste to achieve
a mixture having a weight/weight solvent to biomass ratio of between about 1:1 to about 1:10.
The algae is allowed to settle in a ng vessel, and a solvent / water mixture 360 is removed
by, for example, siphoning and/or decanting. The solvent can be recovered and reused by well-
known techniques, such as distillation and/or pervaporation. The ing wet biomass 370 is
expected to have a solids content of about 30% to about 60% w/w in an alcohol and water
solution.
Solvents ideal for dewatering are industrially common water-soluble ts with
densities over 1.1 g/mL or below 0.9 g/mL. Examples include isopropanol, acetone,
acetonitrile, t-butyl alcohol, ethanol, methanol, 1-propanol, heavy water (D20), ne
, and/or glycerin. If the solvent density is over 1.1 g/mL then the algae biomass would
float rather than create a sediment at the bottom of the settling vessel.
is a schematic diagram of an ary embodiment of an extraction
system
200. The wet or dry algal biomass is transported using methods known in the
art, including,
but not limited to a moving belt, a screw
conveyor, or through extraction chambers. The
solvent for extraction is recirculated from a e tank assigned to each biomass slot position.
The extraction mixture is filtered, returning the biomass solids back into the slot and the
extract
into the storage tank. The solids on the belt move periodically based on the residence time
ement for extraction. The extracts in each e tank may either be replenished at
saturation or uously replaced by fresh solvent. This would also reduce the downstream
processing time and cost drastically. This embodiment ses a primary reservoir 210, a
transport mechanism 220, a plurality of separation devices 241-248 (2.g.
, membrane filtration
devices), a ity of extraction reservoirs 261—268, and a plurality of recycle pumps 281—287.
In this embodiment, y reservoir 210 is divided
up into a plurality of inlet reservoirs 211-
218.
During operation, algal biomass 201 is placed a first inlet reservoir 211 near a first
end 221 of transport mechanism 220. In addition, solvent 205 is placed into inlet reservoir 218
near a second end 222 of transport mechanism 220. Transport mechanism 220 directs the algal
biomass along transport mechanism 220 from first end 221 towards second end 222. As the
PCT/USZOIZ/027537
algal biomass is transported, it passes through the plurality of tion devices 241-248 and
is separated into fractions of varying polarity. The diffusate portions that
pass through
separation devices 241-248 are directed to reservoirs 261-268.
For example, the diffusate portion of the algal biomass that
passes h the first
separation device 241 (e. g., the portion ning liquid and particles small enough to pass
through tion device 241) is directed to the first reservoir 261. From first reservoir 261,
the diffusate portion can be recycled back to first inlet reservoir 201. The retentate portion of
the algal biomass that does not pass through first separation device 241 can then be directed by
transport mechanism 220 to second inlet reservoir 212 and second separation device 242,
which can comprise a finer tion or filtration media than the first separation device 241.
The segment of the diffusate portion that
passes through second separation device
242 can be directed to second reservoir 262, and then recycled back to second inlet reservoir
212 Via recycle pump 282. The retentate or extracted portion of the algal biomass that does
pass through second separation device 242 can be directed by transport mechanism 220 to third
inlet reservoir 213. This process can be ed for inlet oirs 213-218 and separation
devices 243-248 such that the retentate portions at each stage are directed to the uent
inlet reservoirs, while the diffusate portions are directed to the recycle oirs and ed
back to the current inlet reservoir.
In exemplary embodiments, the first fraction will be extracted with the highest
water to slightly nonpolar solvent ratio, i.e., most polar mixture, while the last on will be
extracted with the most pure slightly nonpolar solvent, i.e. the least polar mixture. The
process
therefore extracts components in the order of decreasing polarity with the fraction. The
function ofthe first fraction is to remove the residual water and facilitate the solvent extraction
process. The fractions that follow are rich in polar lipids, while the final fractions are rich in
neutral lipids.
The oil fraction can be esterified to liberate the long chain unsaturated fatty acids.
The noids and long chain rated fatty acids can be separated from the oil using
processes such as molecular lation in conjunction with non-molecular distillation. All of
the fatty acids can be separated from the carotenoids using the molecular distillation. The
distillates can be fractionated using a simple distillation column to separate the lower chain
fatty acids for refining. The long chain rated fatty acids remain as high boiling residue in
the column.
W0 2012/138438
In some non-limiting embodiments, the tion system and methods described
herein incorporate one or more steps to isolate protein material from the oleaginous material
(e.g., algal biomass). Such protein extraction steps employ pH ment(s) to e
ion and extraction of protein. For example, in one non-limiting ment, the pH of
the solvent in the first separation device is zed for protein extraction, resulting in
a first
fraction that is rich in protein material. The pH of the protein extraction
step is adjusted
depending on the pKa of the proteins of interest. The pKa of a protein of interest may be
ascertained using methods known to one of skill in the art, including, but not limited
to using
the Poisson—Boltzmann equation, empirical methods, molecular dynamics based methods,
the use oftitration curves.
In some embodiments, the solvent pH is alkaline. For example, in some
embodiments, the t pH is greater than about 10. In other embodiments, the solvent pH
ranges from about 10 to about 12. In further embodiments, the solvent pH is about l0, about
11, or about 12. In other embodiments, the t pH is acid. For example, in some
embodiments, the solvent pH is less than about 5. In other embodiments, the solvent pH
ranges
from about 2 to about 5. In further ments, the solvent pH is about 2, about 3, about 4,
about 4.5, or about 5. The extracted portion of the first separation device is then directed
subsequent inlet reservoirs to achieve extraction and fractionation based on polarity. In another
non—limiting embodiment, protein material is separated in the final separation device by similar
means (i.e., solvent pH adjustment).
Adjustment of solvent pH is accomplished in ance with methods known to
those of skill in the art. For example, acid pH is achieved by mixture of
an appropriate acid
into the solvent stream. Exemplary acids useful for protein extraction include, t
limitation, phosphoric acid, sulfuric acid, and hydrochloric acid. Similarly, alkaline pH is
achieved by addition and mixture of an appropriate base into the solvent
stream. Exemplary
bases useful for protein extraction include, without limitation, potassium hydroxide,
sodium hydroxide.
In some embodiments, protein tion is performed in
a system separate from the
extraction and fractionation system described . For example, in some embodiments, an
algal biomass is soaked in a pH-adj usted solvent mixture, followed by isolation via an
riate separation technique (e.g, centrifugation, or filtration). The remaining solid is then
introduced into an extraction and fractionation system based
on polarity, as bed herein.
W0 38438 PCT/U82012/027537
Similarly, in some embodiments, the remaining extract from an extraction and fractionation
process based on polarity is exposed to a pH-adjusted solvent mixture to isolate protein
material at the end of the extraction process.
As shown in the solvent selection and the theory of fractionation based
polarity were developed by extensive analysis of ts and the effect on extraction using the
Sohxlet extraction s, which allows the separation of lipids from a solid material. The
t tion system was utilized for rapid screening solvents for lipid class selectivity
and recovery. Solvents from various chemical classes encompassing a wide
range of polarities
such as s, cycloalkane, alkyl halides, esters, ketones, were tested. Prior to the extraction,
the lipid content and composition of the biomass to be extracted
was tested in triplicate using
the standard methods for algae oil estimation such as the Bligh-Dyer lipid extraction method.
The biomass contained 22.16% total lipid, ofwhich 49.52%
was neutral lipid.
ts the data gathered by extraction of a dry algal mass using s
polar and nonpolar solvents combined with a Sohxlet extraction process. ing on the
chain length of the alkane solvent, 60-70% purity ofneutral lipids and 15-45% of total lipid
recovery can be achieved without disruption and solvent extraction. The longest chain alkane
solvent tested, e, red 60% of the neutral lipids and 42% of the total lipid. As
shows, the results of extraction of dry algal mass using solvents and conventional
extraction
methods such as hexane are inefficient, expensive, and result in
poor . The systems and
methods discloses herein address these inefficiencies by controlling the tion of slightly
nonpolar solvent to water in order to separate out components of differing polarities with
minimal loss of components.
[0138} The lower carbon alcohol solvents were more selective for polar lipids. The neutral
lipid purity was 22% for methanol and 45% for ethanol. pyl alcohol did not show any
selectivity between polar and nonpolar lipids, resulting in a 52% pure neutral lipid product.
Methanol recovered 67% of the total lipids and more than 90% of the polar lipids. Therefore,
methanol is an excellent candidate for an ment of the
present invention wherein
methanol can be used to selectively extract polar lipids from an oleaginous material prior
extracting the l lipids using heptane or hexane. The other solvent classes tested did not
show any selectivity towards lipid class since the neutral lipid purity
was close to 49%, similar
to the lipid composition present in the original biomass. Furthermore, the total lipid recovery
W0 2012/138438 PCT/U82012/027537
achieved with these solvents ranged from about 15—35%, rendering these solvents unsuitable
for the ive extraction of particular lipid classes or total lipid extraction.
The results from the Sohxlct is were confirmed using the standard bench scale
batch solvent extraction apparatus described below in Example 1. The solvents selected were
methanol for the first step to recover polar , and eum ether in the second
step for
recovery of neutral lipids. All of the extractions were performed with a 1:10 solidzsolvent
ratio. Each extraction step in this experiment was 1 hour long. Other ments done (data
not shown) indicate that about 45 minutes or longer is long enough for the extraction
to be
successful. This retention time is dependent on the heat and mass transfer ofthe
system.
The methanol extractions were performed at different temperatures, 40 0C, 50 OC,
and 65 °C, in order to determine which was l. The petroleum ether extraction
performed at 35°C, close to the boiling point of the t. Petroleum ether was chosen
e of its high selectivity for neutral lipids, low boiling point, and the product quality
observed after extraction.
shows that the neutral lipid purity in a petroleum ether extraction carried
out after a ol extraction step at 65°C is over 80%, demonstrating that the combination of
these two extraction steps enhanced the neutral lipid content of the final crude oil product.
shows that the total neutral lipid
recovery was low and there was a significant amount
ofneutral lipid loss in the first step.
To minimize the loss of neutral lipids in the methanol extraction
step, the polarity of
the solvent can be increased by adding water to the solvent. and 5B show the results
of extracting the entioned biomass with 70% v/v
aqueous methanol followed by
extraction with petroleum ether. shows that the neutral lipid purity was much higher
in the petroleum ether extraction than was achieved by the
use ofpure methanol. Moreover,
the loss of neutral lipids was greatly reduced by the use of
aqueous methanol in the first
extraction step. As seen in , methanol extraction at higher
temperatures improved
neutral lipid purity but slightly decreased the total lipid
recovery in the subsequent step.
In some exemplary embodiments the temperature of the extraction
process is
controlled in order to ensure optimal stability of algal components
present in the algal s.
Algal proteins, carotenoids, and chlorophyll are examples of algal components that exhibit
ature sensitivity. In other embodiments, the temperature is increased after the
temperature sensitive algal components have been extracted from the algal biomass.
PCT/U82012/027537
In still other exemplary embodiments, the temperature of the extraction
process is
adjusted in order to optimize the yield of the desired product. Extractions can be run from
ambient temperature up to, but below, the boiling point of the extraction mixture. In still other
embodiments, the temperature ofthe extraction process is changed depending on the solubility
ofthe desired product. In still other embodiments, the extraction temperature is optimized
depending on the algal strain of the biomass to be extracted. ed extraction temperatures
increase the solubility of d nds and reduce the viscosity of the tion mixture
enhancing extraction ry.
In some embodiments, the extraction is run under
re to e the boiling
point of the extraction mixture. In these implementations, the pressure is increased to the
degree ary to prevent boiling, while maintaining the temperature of the extraction
mixture below a temperature at which any of the desired products would begin to degrade,
denature, decompose, or be destroyed.
In some exemplary embodiments, the extraction is performed near the boiling point
ofthe solvent used, at the conditions under which the extraction is performed (e.
g., atmospheric
or elevated pressures). In other embodiments, the extraction is performed near the g
point of the extraction mixture, again accounting for other extraction conditions. At such
temperatures, vapor phase penetration of the solvent into the algal cells is faster due to lower
mass transfer resistance. If the extraction temperature is allowed to cantly exceed the
boiling point of the solvent, the solvent—water system can form an azeotrope. Thus,
maintaining the system at or near the boiling point of solvent would generate enough vapors to
e the extraction, while ng expense. In addition, the solubility of oil is increased at
higher temperatures, which can further increase the effectiveness of extraction at atures
close to the solvent boiling point. shows the total lipid recovery in the
aqueous
ol-petroleum ether extraction scheme. Although performing the methanol extraction
near its boiling temperature slightly decreases the neutral lipid recovery
as observed in , it enhances the total lipid recovery.
In other embodiments, the extraction is carried out under ambient lighting
conditions. In other ments, the extraction is carried out in an
opaque container such as,
but not d to, a steel tube or casing, in order to protect light sensitive algal
components
from degradation. Carotenoids are light sensitive algal components.
W0 2012/138438 PCT/U52012/027537
In other exemplary ments, the extraction takes place under normal
atmospheric conditions. In still other embodiments, the extraction takes place under a nitrogen
atmosphere in order to protect algal components prone to oxidation. In still other
embodiments, the extraction takes place under an atmosphere of inert gas in order to protect
algal components prone to oxidation. Algal components that might be prone to oxidation
include carotenoids, chlorophyll, and lipids.
In exemplary embodiments, the t-to-solid ratio for the tion is between
3—5 based on the dry weight of the solids in the biomass. The residual algal biomass is rich
carbohydrates (e.g., starch) and can be used as a feed stock to produce the solvent used for
extraction.
shows the effect of the solvent to solid ratio on the total lipid
recovery. As
the solvent to solid ratio was increased, there was a corresponding and drastic increase in
total
lipid recovery. It is believed that this was because of the lower solubility of lipids in methanol
as compared to other commonly used oil tion solvents such
as hexane.
The solubility of components is affected by the polarity of solvent used in
extraction process. The solubility properties can be used to determine the ratio of
wet biomass
to solvent. For example, a 40% w/w wet biomass has 40
g biomass and 60 g water for every
100 g ofwet biomass. If 100 g of ethanol is added to this mixture, the ratio of ethanol
to wet
biomass is 1 part wet biomass to 1 part ethanol and the concentration of l in the mixture
is 100/(100+60) equals about 62% w/w of ethanol in the liquid phase. 62% w/w of
ethanol in
ethanol water mixture corresponds to a ty index of 6.6, calculated by weight
averaging the polarities of the ents. Ethanol, having a polarity index of 5.2, and water,
having a ty index of 9, in a mixture containing 62% ethanol and 38% water results in a
polarity index of (0.62*5.2+.38*9) about 6.6. The polarity index of the e for extraction
ofpolar lipids and neutral lipids is calculated to be about 5.8 and 5.4 respectively.
In light of
the instant disclosure, one of skill in the art would be able to formulate
a solvent set that can
ively extract these components.
In r e, if the extraction t is a 1:1 mixture of isopropyl alcohol
and ethanol, the polarity of this solvent is ((3.9+5.4)/2) which is about 4.65. The
ratio of
solvent to wet biomass would be calculated to match the polarities. To
get a 6.6 polarity index,
we would need to make a 55% w/w of IPA-water mixture calculated by solving the following
algebraic equation:
W0 2012/138438 PCT/U$2012/027537
X*4.65+(1—x)*9=6.6
x = (9-6.6)/(9-4.65) = 0.55
55% w/w*ofsolvent mix in t ter
For a 40% w/w wet biomass, the wet biomass to IPA ratio is (l-0.55)/0.6 ~ 0.75.
With a 40% w/w wet biomass this would correspond to a ratio of 100
parts wet
biomass to 75 parts solvent mixture. A 40% W/w wet biomass has 40
g biomass and 60 g water
for every 100 g of wet biomass. If 75 g of solvent mixture is added to this e, the
concentration of solvent in the mixture is (75/(75+60)) is about 55% w/w of solvent mixture in
the solvent mixture—water solution. This calculation can be used to obtain the solvent s
ratio at each extraction stage and for each product. A few nonlimiting examples of solvent
sets
appear in Table 3.
Table 3
......................Extraction"?
; g s 3 5 §Solvent- solvent
:parts wet2parts EBiomass Parts Dry EParts iwater :polarity
§95% ethanol 5% methanol mixture
395% ethanol 5% IPA mixture
One step Polar lipids tion
EEthanol
gPropanol
21:1 lPA EtOH mixture
95% ethanol water mixture
i 95% ethanol 5% methanol mixture
' 5% ethanol 5%lPA mixture
95% l 5% met
§95% ethanol 5%IPA mixture
PCT/U52012/027537
The extraction mixture described in all examples, is made
up of a substantially solid
phase and a substantially liquid phase. These phases are then separated post tion. This
can then be followed by removal of the liquid solvent from the liquid phase, yielding
extraction product. In some embodiments, the solvent is evaporated. In such an
implementation, a liquid-liquid extraction technique can be used to reduce the amount of
solvent that needs to be evaporated. Any solvents used can be recycled if conditions allow.
It was theorized that treatment of the algal biomass prior to extraction would
enhance the productivity and efficiency of lipid extraction. In this direction an experiment was
done comparing the effect of adding a base or another organic solvent to
an algal biomass to
change the surface properties and enhance extraction. A variety of treatments ing
aqueous ol, aqueous sodium hydroxide, and aqueous DMSO were attempted. As
demonstrates, the addition of 5% DMSO increases the lipid ry 3-fold. These tion
steps may be exploited to dramatically reduce the methanol extraction steps. However, the
solutions used in the above experiments may not be ideal for use on larger scales due
to the
high cost, viscosity, and ability to r and recycle DMSO.
is a chart showing the effect of an eight step methanol extraction
on the
cumulative total lipid yield and the purity of the ted neutral lipid. In this embodiment,
112 grams of wet biomass (25.6% dry weight), was extracted with 350 mL
pure methanol and
heating for 10 minutes at 160 W irradiance power in each step. This ed in an extraction
ature of about 75°C, which was near the boiling point of the extraction mixture. Using
this process, it was determined that it is possible to obtain highly
pure neutral lipids from algal
oil once the majority of the polar lipids have been ted. shows that it is possible to
isolate high purity neutral lipid once the polar lipids are all extracted. In this case a 5% yield of
total biomass was achieved with over 90% neutral lipids purity in methanol extraction
steps 5
through 8. Furthermore, due to the boiling point of the extraction mixture, most of the water in
the s is completely extracted in the first extraction step, along with carbohydrates,
ns and metals.
shows that ry of lipids can be made more efficient by the
use of
ethanol to extract lipids and protein from wet biomass. By using ethanol, 80% total lipid
recovery can be achieved in about 4 steps rather than the 9 generally needed by using
methanol. This increase in recovery may be attributed to greater solubility of lipids in ethanol
as ed to methanol. Furthermore, the boiling point of aqueous ethanol is higher than
W0 2012/138438 PCT/U82012/027537
aqueous ol, facilitating fiirther ry of lipids. This is e the higher
temperature renders the oil less viscous, thereby improving ability. Another distinct
advantage of this process is using the residual ethanol in the oil fraction for transesterification
as well as lowering the heat load on the biomass drying operation.
Further, FIG. lO demonstrates that the initial ons are pid rich, containing
proteins and other highly polar molecules, followed by the polar lipid rich ons and finally
the neutral lipid fractions. Hence with a proper design of the extraction
apparatus, one can
recover all the three products in a single extraction and fractionation process.
r embodiment of the current invention utilizes microwaves to assist
extraction. Based on previously gathered data disclosed in this application, it is shown that
methanol is the best single solvent for extraction of all lipids from algae. Hence, a single
solvent le step tion, as described in Example 1 of the instant application, was
med in order to gather data on the efficacy of a one solvent microwave extraction system.
is a logarithmic plot comparing the extraction time and total lipid
recovery
of conventional extraction and microwave-assisted extraction. Based
on the slope of the curve,
it was calculated that the microwave system reduces the extraction time by about five fold
more. While the conventional methods have a higher net lipid
recovery, this is due to higher
recoveries of polar lipids. Based on these results, the conditions for extraction of dry algal
biomass using solvents with and without microwave assistance have been optimized. Some
embodiments ofthe invention use traditional microwave apparatus, which emit wavelengths
that excite water molecules. r embodiments of the invention utilize customized
microwave apparatus capable of exciting different solvents. Still other embodiments of the
invention utilize custom microwave apparatus capable of exciting the lipids
present in the algal
biomass. In some embodiments, the lipids present in the algal biomass
are excited using
microwaves, thereby enhancing the separation and extraction of the lipid components from the
algal s.
Moisture content is another parameter of biomass that will influence the efficiency
of oil extraction. In some embodiments of the present invention, dry algal
mass is extracted
and onated. In other embodiments, the algal mass is wet. Biomass samples with algae
mass contents of 10%, 25%, and 33% were used to investigate the influence of moisture
extraction performance.
PCT/U52012/027537
A shows an illustrative s 400 for a step—wise extraction of products
from an algae biomass. All units in FlG. 12A are in pounds. A shows a mass e
ofthe process 400, while the details of the equipment and/or systems for performing the
process are described elsewhere herein. A biomass containing 5 pounds of algae has about
0.63 pounds ofpolar lipids, 1.87 pounds l lipids, 1 pound protein, and 1.5 pounds
carbohydrates. The biomass and 1000 pounds of water is processed in a dewatering step 405,
which separates 950 pounds of water from the mixture and
passes 5 pounds of algae in 45
pounds of water to a first extraction step 410. Any of the dewatering techniques disclosed
herein can be used tin dewatering step 405. In the first extraction step 410, 238 pounds of
ethanol and 12 pounds ofwater are combined with the algae and water from the previous
step.
The first extraction step 410 has a liquid phase of about 80.9% W/W ethanol. A first liquid
phase of231 pounds of ethanol, 53 pounds of water, and 0.5 pounds of algal proteins are
red, from which water and ethanol are removed by, e.g.
, evaporation, g a protein-
rich product 415. Solvent red from the evaporation can be recycled to the first extraction
step 410.
A first solid phase from the first extraction step 410 is passed to
a second extraction
step 420; this first solid phase includes 4.5 pounds of algae, 2.6 pounds of water, and 10.9
pounds of ethanol. Eighty-six pounds of ethanol and 4 pounds of water are added to the first
solid phase from the previous step. The second extraction step 420 has
a liquid phase of about
93.6% w/w ethanol. A second liquid phase of 85.9 pounds ethanol, 5.9 pounds
water, and 0.6
pounds polar lipids are recovered, from which water and ethanol are removed by,
e.g.,
evaporation, leaving a polar lipid-rich product 425. Solvent recovered from the ation
can be recycled to the second extraction step 420.
A second solid phase from the second extraction step 420 is passed
to a third
extraction step 430; this first solid phase includes 3.9 pounds of algae, 0.7 pounds of
water, and
11 pounds of ethanol. Seventy-found and a half pounds of ethanol and 3.5 pounds of water are
added to the second solid phase from the previous step. The third extraction
step 430 has a
liquid phase of about 95.4% w/w ethanol. A third liquid phase of 78.9 pounds ethanol, 3.9
pounds water, and 1.6 pounds neutral lipids are recovered, from which water and ethanol are
removed by, e.g., evaporation, g a neutral lipid-rich product 435. Solvent recovered from
the evaporation can be recycled to the second extraction step 430 A solid phase of
2.3 pounds
algac, 0.3 pounds water, and 6.6 pounds l rcmain.
W0 2012/138438 PCT/U52012/027537
As demonstrated in A, the resulting lipid profile with each sequential
ethanol extraction step was largely ced by the moisture content in the starting algae.
Models of process 400 were run on three different biomass collections, each having
a different
initial water content. As the initial water content decreased, the m lipid
recovery step
changed from the third extraction step to a fourth (not shown). However, the overall lipid
ry from these three biomass samples were quite similar, all above 95% of the total lipid
content of the algal biomass.
When algal mass with higher moisture content was used, the ethanol concentration
in the s ethanol mixture was much lower, and consequently the neutral lipid
percentage
in the crude extract was also lower. It has been reported that dewatering an algae paste with
90% water is a very energy intensive
process. The methods described herein unexpectedly can
be used to successfully extract and onate an algal mass containing mostly
water. As
overall lipid recovery was not significantly influenced by ng from
an algae paste
containing 90% water (10% algal solids), unlike conventional extraction methods, the methods
disclosed herein do not require the use of an energy intensive drying
step.
B shows an illustrative implementation 500 of one of the extraction
steps of
process 400. An algae biomass and t mixture 505 is provided to an extraction vessel
510. After the algae is extracted (as described elsewhere herein), the mixture is provided
to a
coarse filtration system 515, such as a ed metal tube filter, which separates the mixture
into a liquid phase and a solid phase. The solid phase is passed to
a downstream extraction
step. The liquid phase is passed to a solvent l system 520, e.g., an evaporator, to reduce
the solvent (e.g., ethanol) content in the liquid phase. The liquid phase remaining after
solvent
removal is, optionally, passed to a centrifuge 525. Any solids remaining in the t
removal
system are recycled or discarded. Centrifuge 525 assists in separating the desired algal product
(e.g., ns or lipids) from any remaining water and/or solids in the liquid phase.
shows an example of a
process 600 by which an algal mass can be
processed to form or recover one or more algal products. In this example, an algal biomass is
extracted in a step-wise manner in a front-end
process 605 using the methods disclosed .
The extraction and separation steps are followed by an esterification
process 610, a hydrolysis
process 615, a hydrotreating process 620, and/or a distillation process 625 to further e
components and products. The components and products e algal lipids, algal proteins,
glycerine, carotenoids, nutraceuticals (e.g., long chain unsaturated oils and/or esters), fuel
esters (generally, the esters having chain lengths of C20 or shorter), fuels, fuel additives,
naphtha, and/or liquid petroleum substitutes. In preferred embodiments the fuel esters are C16
chain lengths. In others, the fuel esters are C18 chain lengths. In still other embodiments, fuel
esters are a mixture of chain lengths, C20 or shorter.
The esterification process 610, ysis
process 615, hydrotreating s 620,
and distillation process 625 are optional and can be used in various orders. The dashed
arrows
and dotted arrows te some, but not all, of the options for when the hydrolysis,
hydrotreating, and/or distillation processes may be performed in the processing of the lipid
fractions. For example, in some embodiments of the ion, after extraction and/or
separation are carried out, the neutral lipids fraction can be directly hydrotreated in order to
make fuel products and/or additives. Alternatively, in other embodiments, the neutral lipid
fraction can be passed to esterification process 610.
Esterification s 610 can include techniques known in the art, such
as acid /
base catalysis, and can include transesterification. Although base catalysis is not excluded for
producing some products, acid catalysis is preferred as those techniques avoid the soaps that
are formed during base catalysis, which can complicated ream processing. Enzymatic
esterification ques can also be used. fication can process substantially pure lipid
material (over 75% lipid, as used herein). After esterification, glycerine byproduct can be
removed. The esterified lipids can then undergo molecular and/or nonmolecular distillation
(process 625) in order to separate esterified lipids of different chain lengths as well as
carotenoids present in the lipid on. The esterified lipids can then be passed to
reating process 620 to generate jet fuel, biodiesel, and other fuel products. Any
hydrotreating process known in the art can be used; such a process adds hydrogen to the lipid
molecules and removes oxygen molecules. Exemplary conditions for hydrotreating comprise
reacting the triglycerides, fatty acids, fatty acid esters with hydrogen under high pressure in the
range of 600 psi and temperature in the range of 600°F. Commonly used sts are NiMo or
CoMo.
Hydrotreating the fiiel esters rather than the raw lipids has several advantages.
First, the fication s 610 reduces the levels of certain phosphorus and metals
compounds present in algal oils. These materials are poisons to catalysts typically used in
hydrotreating processes. Thus, esterification prior to hydrotreating prolongs the life of the
hydrotreating catalyst. Also, esterification reduces the molecular weight of the compounds
W0 38438
being hydrotreated, thereby improving the performance of the hydrotreating process 620.
Further still, it is advantageous to retain the fuel esters from the distillation
process 625 to be
hydrotreated in a vaporous form, as doing so reduces the energy needed for hydrotreating.
In some embodiments ofthe invention, the neutral algal lipids are directly
hydrotreated in order to convert the lipids into fuel products and additives. While in other
implementations, the neutral lipids are cstcrificd and separated into carotenoids, long chain
rated esters, eicosapentaenoic acid (EPA) esters, and/or fuel esters via distillation
process 625. Distillation process 625 can include molecular lation as well as
any of the
distillation techniques known in the art. For example, the distillates can be fractionated using a
simple distillation column to separate the lower chain fatty acids for refining. The long chain
unsaturated fatty acids remain as high boiling residue in the column. In some embodiments,
the remaining vapor can then be sent to the hydrotreating
process. Two of the advantages of
the present invention are that it yields pure feed as well as a
vapor product, which favors the
energy ive hydrotreating reaction, as described above.
In some embodiments ofthe invention, polar lipids (and, optionally, l lipids)
are yzed in hydrolysis process 615 before being passed to the esterification
process.
Doing so unbinds the fatty acids of the algal lipids, and s a greater amount of the algal
lipids to be formed into useful products.
is a flowchart showing a
process 700 for producing nutraceutical products
from neutral lipids. In one implementation ofprocess 700, neutral lipids
are fed to an
adsorption process 705 that separates carotenoids from EPA-rich oil. The neutral lipids can be
from an algae source generated by any of the selective extraction techniques disclosed
herein.
However, the neutral lipids can be from other s, such as plant sources.
Adsorption process 705 es contacting the l lipids with an adsorbent to
adsorb the carotenoids, such as beta carotene and phylls. In one implementation, the
adsorbent is Diaion HP2OSS (commercially available from ITOCHU als
America,
Inc.). The neutral lipids can contact the adsorbent in a batch-type process, in which the neutral
lipid and adsorbent are held in a vessel for a selected amount of time. After the contact time,
the absorbent and liquid are separated using techniques known in the art. In other
implementations, the adsorbent is held in an adsorbent bed, and the neutral lipids are passed
through the adsorbent bed. Upon passing through the adsorbent bed, the carotenoids content of
the neutral lipids is reduced, thereby producing an oil rich in EPA.
W0 2012/138438 PCT/U52012/027537
The carotenoids can be recovered from the adsorbent material by ng the
adsorbent with an appropriate t, ing, but not limited to, alcohols such
as ethanol,
isopropyl alcohol , butanol, esters such as ethyl acetate or butyl acetate, alkanes such as
hexane, and e.
In yet another embodiment of the invention, chlorophylls and carotenoids
isolated from the neutral lipids. The adsorption
process can be performed using a hydrophobic
adsorbent such as polystyrene-divinylbenzene resin (PS-DVB) or with higher carbon loading
resin. Some examples of the resins are XAD 16, XAD 4 from Rohm and Hass (Philadelphia,
PA) or HP20, SP—850 from Mitsubishi Chemical ries Limited (Tokyo, Japan) distributed
by ltochu Chemicals America, Inc, White Plains, NY). The extraction on dissolved in
aqueous ethanol would be passed over a packed column to selectively retain the chlorophylls
and noids. Upon reaching the adsorption loading capacity, the column would be washed
with a hydrophobic solvent such as hexane. The
pure noids and chlorophyll on
dissolved in hexane is evaporated under mild conditions to obtain a concentrate. The
pure
carotenoids and chlorophyll could also be crystallized and precipitated in the solution.
In yet another embodiment of the ion, extracting neutral lipids from the algal
biomass, followed by a membrane diafiltration step for the separation of chlorophylls and
carotenoids from the neutral lipids. Membrane diafiltration works based
on the principle of
selectively g the product through a membrane and retaining the remaining components of
the feed mixture. In this case, we would use a solvent stable nanofiltration membrane such
SelRO ts from Koch membrane systems ngton, MA). The neutral lipids
extract
suspended in aqueous ethanol would be filtered through the membrane to selectively separate
the unbound carotenoids and chlorophylls. The feed is continuously diluted with ethanol
until
all the carotenoids and chlorophylls are washed off and collected in
In yet another embodiment of the invention, chlorophylls and carotenoids
isolated from the polar lipids. The adsorption
process can be performed using a hydrophobic
adsorbent such as polystyrene-divinylbenzene resin (PS—DVB)
or with higher carbon loading
resin. Some examples of the resins are XAD 16, XAD 4 from Rohm and Hass (Philadelphia,
PA) or HP20, SP—850 from Mitsubishi Chemical Industries Limited (Tokyo, Japan) distributed
by ltochu Chemicals a, Inc, White Plains, NY). The polar lipids extract is dissolved in
aqueous ethanol would be passed over a packed column to selectively retain the chlorophylls
and carotenoids. Upon reaching the adsorption loading capacity, the column would be
washed
W0 2012/138438
with a hydrophobic solvent such as . The
pure carotenoids and phyll fraction
dissolved in hexane is evaporated under mild conditions to obtain a concentrate. The
pure
carotenoids and chlorophyll could also be llized and precipitated in the solution.
In yet another embodiment of the invention, extracting polar lipids from the algal
biomass, followed by a membrane diafiltration step for the separation of phylls and
carotenoids from the polar lipids. Membrane diafiltration works based on the principle of
selectively eluting the product through a membrane and retaining the remaining components of
the feed mixture. In this case, we would use a solvent stable nanofiltration membrane such
SelRO from Koch membrane systems (Wilmington, MA). The polar lipids extract suspended in
aqueous ethanol would be filtered through the membrane to selectively separate the unbound
carotenoids and chlorophylls. The feed is continuously diluted with ethanol until all the
carotenoids and chlorophylls are washed off and collected in permeate.
In yet another embodiment of the invention, a method of making biofiiels includes
dewatering substantially intact algal cells to make an algal biomass, extracting neutral lipids
from the algal biomass, followed by an adsorption step for the separation of chlorophylls and
carotenoids from the neutral lipids. The method also includes esterifying the neutral lipids with
a catalyst in the presence of an alcohol, and separating a water soluble fraction comprising
glycerin from a water insoluble fraction comprising fuel esters. The method still further
es ling the fuel esters under vacuum to obtain a C16 or shorter fuel
esters on, a
C16 or longer fuel ester fraction, and a residue comprising omega—3 fatty acids and
enating and deoxygenating at least one of (i) the C16 or shorter fuel esters to obtain a jet
fuel blend stock and (ii) the C16 or longer fuel esters to obtain
a diesel blend stock.
In yet another embodiment of the invention, a method ofmaking biofuels includes
dewatering substantially intact algal cells to make an algal s, extracting neutral lipids
from the algal biomass, followed by a membrane diafiltration
step for the separation of
chlorophylls and carotenoids from the l . The method also includes esterifying the
neutral lipids with a catalyst in the presence of an alcohol, and separating
a water soluble
fraction comprising glycerin from a water insoluble on sing fuel
esters. The
method still further includes distilling the fuel esters under vacuum to obtain
a C16 or shorter
fuel esters fraction, a C16 or longer fuel ester fraction, and a residue comprising
3 fatty
acids and hydrogenating and deoxygenating at least one of (i) the Cl 6
or shorter fuel esters to
obtain a jet fuel blend stock and (ii) the C16 or longer fuel esters to obtain
a diesel blend stock.
W0 2012/138438 PCT/U52012/027537
In yet another ment of the invention, a method of making nutraceuticals and
health foods es dewatering substantially intact algal cells to make an algal biomass,
ting neutral lipids from the algal biomass, followed by an adsorption step for the
tion of chlorophylls and carotenoids from the l lipids. The neutral lipids resulting
from this step would be rich in omega-3 fatty acids with a balanced ratio of monounsaturated,
polyunsaturated and saturated fatty acids. This can be sold as high quality oil for better health.
In yet another embodiment of the invention, a method of making nutraceuticals and
health foods includes dewatering substantially intact algal cells to make an algal biomass,
extracting l lipids from the algal biomass, followed by a ne diafiltration step for
the separation of chlorophylls and carotenoids from the neutral lipids. The neutral lipids
resulting from this step would be rich in omega-3 fatty acids with a balanced ratio of
monounsaturated, saturated and saturated fatty acids. This can be sold as high quality oil
for better health.
is a flowchart showing a process 800 for producing fuel products 830 from
neutral lipids 805. The l lipids can be from an algae source generated by
any of the
selective extraction techniques disclosed herein. However, the l lipids can be from other
sources, such as plant sources. The neutral lipids are treated in a degumming process 810, in
which the lipids are acid washed to reduce the levels of metals and phospholipids in the l
lipids. In some implementations, a relatively dilute solution of phosphoric acid is added
to the
neutral lipids, and the mixture is heated and agitated. The precipitated olipids and
metals are then separated from the remaining oil, for example, by centrifuge.
The treated oil is then passed to bleaching
process 815 to remove chlorophylls and
other color compounds. In some implementations, bleaching
process 815 includes contacting
the oil with clay and or other adsorbent material such as ing clay (Le. bentonite
fuller’s earth), which reduce the levels of chlorophylls and other color compounds in the oil.
The treated oil then is passed to hydrotreating
process 820, which hydrogenates and
deoxygenates the components of the oil to form fuels products, for example, jet fuel es,
diesel fuel additive, and propane. In addition, the hydrotreating process 820 also causes some
cracking and the creation of smaller chain compounds, such as LPG and naptha. Any of the
hydrotreating processes described herein can be used for hydrotreating process 820.
The mixture of compounds created in the hydrotreating
process 820 are passed to a
distillation process 825 to separate them into various fuel products 830. Distillation process
W0 2012/138438 PCT/U82012/027537
825 can include any of the molecular and non-molecular distillation ques described
herein or known in the art for separation of fuel compounds.
In some embodiments of the instant ion, proteins
may be selectively ted
from an algal biomass. Extraction of proteins using the disclosed methods offers many
advantages. In particular, algal cells do not need to be lysed prior to extracting the desired
proteins. This simplifies and reduces costs of extraction. The methods of the instant invention
exploit the solubility s of different classes of proteins in order to selectively extract and
fractionate them from an algal culture, biomass, paste, or cake.
For example, an algal biomass may be subjected to heating and mixing to extract
water and salt soluble proteins called albumins and globulins. This e can then be
subjected to a change in pH to recover the alkali soluble ns called the glutelins. This step
can then be followed by a solvent-based separation of the alcohol soluble proteins called
prolamins. The remaining s would be rich in carbohydrates and lipids.
Proteins can be extracted from both saltwater and freshwater algal cells, as shown in
FIGS. 17 and 18. The presence of salt in the saltwater algal culture or s affects the
extraction of different classes of protein, but the methods disclosed herein enable
one to
selectively extract proteins from either fresh or saltwater algae.
In some embodiments, extraction of proteins from freshwater algal cells is
accomplished by the novel process shown in . Freshwater algal cells or a freshwater
algal biomass are heated and mixed. Mixing can be accomplished by a variety of methods
known in the art such as, but not limited to, stirring, agitation, and rocking. This process
generates a first heated extraction mixture or slurry, comprised of a first substantially liquid
phase and a first substantially solid phase. The solid and liquid phases are then separated.
tion can be accomplished by a variety of methods known in the art including, but not
limited to, eentrifugation, decantation, flotation, sedimentation, and filtration. This first
substantially liquid phase is enriched in n ns.
The first substantially solid phase is then mixed with salt water and heated to
generate a second heated extraction mixture or slurry, comprised of a second substantially
liquid phase and a second substantially solid phase. The salt water may be natural seawater or
may be an aqueous salt solution. An example of such a solution would se about
typically 35 g/L comprising mainly . The solid and liquid phases are then ted.
This second ntially liquid phase is enriched in globulin proteins.
PCT/U52012/027537
The second substantially solid phase is then mixed with water and heated to
generate a third heated extraction mixture or slurry, comprised of a third substantially liquid
phase and a third substantially solid phase. The pH of this third extraction mixture or slurry is
then raised to about 9 or greater, enriching the third substantially liquid phase with glutelin
proteins. The solid and liquid phases are then separated, the third substantially liquid phase
being enriched in glutelin proteins.
The third substantially solid phase is then mixed with a solvent set and heated
generate a fourth heated tion mixture or , sed of a fourth substantially liquid
phase and a fourth substantially solid phase. In one red embodiment, the solvent set
comprises ethanol. In other non-limiting embodiments, the solvent set ses
one or more
ofthe ing ts: methanol, isopropanol, acetone, ethyl
acetate, and acetonitrile. The
solid and liquid phases are then separated. This fourth substantially liquid phase is enriched in
prolamin proteins. The remaining fourth substantially solid phase may be enriched in lipids,
depending on the composition of the ng algal biomass.
In some embodiments, tion of proteins from saltwater algal cells is
accomplished by the novel process shown in . Saltwater algal cells or a saltwater algal
biomass are heated and mixed. Mixing can be accomplished by a variety of s known in
the art such as, but not limited to, stirring, agitation, and g. This process generates a first
heated extraction mixture or slurry, comprised of a first substantially liquid phase and
a first
substantially solid phase. The solid and liquid phases are then separated. Separation can be
accomplished by a variety of methods known in the art including, but not limited to,
centrifugation, decantation, flotation, sedimentation, and filtration. This first substantially
liquid phase is enriched in globulin proteins.
The first substantially solid phase is then mixed with water and heated to
generate a
second heated extraction mixture or slurry, comprised of a second substantially liquid
phase
and a second substantially solid phase. The solid and liquid phases
are then separated. This
second substantially liquid phase is enriched in albumin proteins.
The second substantially solid phase is then mixed with water and heated
generate a third heated extraction mixture or slurry, comprised of a third substantially liquid
phase and a third substantially solid phase. The pH of this third extraction mixture or slurry is
then raised to pH 9 or r, enriching the third substantially liquid phase with glutelin
W0 2012/138438 PCT/U52012/027537
proteins. The solid and liquid phases are then separated, the third ntially liquid phase
being enriched in glutelin proteins.
The third substantially solid phase is then mixed with a t set and heated to
generate a fourth heated extraction mixture or slurry, comprised of a fourth substantially liquid
phase and a fourth substantially solid phase. In one preferred embodiment, the solvent set
comprises ethanol. In other non-limiting embodiments, the solvent set comprises one or more
ofthe following solvents: methanol, isopropanol, acetone, ethyl acetate, and itrile. The
solid and liquid phases are then separated. This fourth substantially liquid phase is enriched in
prolamin proteins. The remaining fourth substantially solid phase may be enriched in lipids,
depending on the composition of the starting algal biomass.
The disclosed methods also provide for the selective extraction of different types of
proteins, as shown in -20. Any of the steps of the entioned extraction process
can be performed separately from the rest of the steps in order to selectively extract
a single
protein product. Two examples of this appear in and 18, as the as demonstrated by the
dashed box around extraction step la.
In a non-limiting e, globulin proteins can be selectively extracted from
freshwater algal biomass by mixing said biomass with salt water and heating to
generate a
heated extraction mixture or slurry, comprised of a ntially liquid phase and
substantially solid phase. The solid and liquid phases can then be separated. The liquid phase
is enriched in globulin proteins. See , extraction step la.
In another non—limiting example, albumin proteins can be selectively extracted from
a saltwater algal biomass by mixing said biomass with water and heating to generate
a heated
extraction mixture or slurry, comprised of a substantially liquid phase and a substantially solid
phase. The solid and liquid phases can then be separated. The liquid phase is enriched in
globulin ns. See , extraction step la.
In a further non~limiting example, prolamin proteins can be ively extracted
from either a freshwater or saltwater algal biomass as shown in . The ive
extraction is accomplished by mixing the algal biomass with a solvent set and heating to
generate a heated extraction mixture or slurry, comprised of a substantially liquid phase and a
substantially solid phase. The solid and liquid phases can then be ted. The liquid phase
is ed in prolamin proteins.
W0 2012/138438 PCT/U52012/027537
In yet another non-limiting e, a protein fraction can be selectively extracted
from either a freshwater or ter algal biomass as shown in . The selective
extraction is lished by mixing the algal biomass with a solvent set to
generate an
extraction mixture or slurry and effecting a pH change in the mixture. The mixture is
comprised of a substantially liquid phase and a substantially solid phase. The solid and liquid
phases can then be separated. The liquid phase is enriched in proteins.
Having been informed of these aspects of the invention, one of skill in the art would
be able to selectively extract a d protein from either a freshwater
or saltwater algal
s by either a single step extraction process, or a multi—step extraction
process. In light of
the instant disclosure, one of skill in the art would be able to hange the order of the above
disclosed multi—step extraction schemes, provided that the protein content of the algal
mass and
the solubility properties of the proteins of st are taken into account. Other embodiments
ofthe disclosed methods may incorporate a wash step between each extraction
step.
For any of the disclosed protein extraction methods, the extraction mixture/slurry
may be maintained at a heated temperature for a period of time. In some embodiments, the
extraction mixture is maintained at a heated temperature for between about 20 minutes to about
90 minutes. In some aspects, the tion mixture is maintained at a heated temperature for
between about 20 minutes and about 60 minutes. In other aspects, the tion mixture is
maintained at a heated temperature for between about 45 minutes to about 90 minutes.
In some embodiments, the extraction mixture/slurry
may be heated to atures
less than about 50°C. In some aspects, the albumin, globulin, and glutelin proteins
extracted at temperatures of less than about 50°C. In other embodiments the tion
mixture/slurry is heated to a temperature close to the boiling point of extraction mixture/slurry.
In some aspects, the prolamin proteins are extracted at atures close to the boiling point
ofthe extraction mixture/slurry. In other embodiments, the pressure is increased above
heric pressure, up to and including, 5Opsi, during the heating and mixing steps to
enhance extraction.
Example 1
Green microalgae Scena’esmus dz'morphus (SD) were cultured in outdoor panel
ioreactors. SD samples of varying lipid contents were harvested, After removal of bulk
water by centrifugation, the algal samples were stored as 3-5 cm algae cakes at —80°C until
use.
W0 2012/138438 2012/027537
A pie-calculated amount ofwet algal biomass (15
grams dry algae weight equivalent) and 90
mL of ethanol solvent was added into a three-neck flask equipped with condenser, mechanical
stirring and a thermocouple. In one experiment, the mixture was refluxed for 10 min under
microwave irradiance. In a second, the e was refluxed for 1h with electronic heating.
Afterwards, the e was cooled to room temperature and separated into a diffusate and
retentate by filtration.
The total lipids of algal samples were ed using a chloroforrn—methanol—water
system according to Bligh and Dyer’s lipid extraction method. This total lipid value was used
as reference for the lipid recovery calculation. Total lipids were further separated into neutral
lipids and polar lipids by standard column chromatography method using 60—200 mesh silica
gel (Merck Corp, Germany). Each lipid fraction was transferred into a pre-weighed vial,
initially evaporated at 30 °C using a rotary evaporator (Biichi, Switzerland) and then dried
under high vacuum. The dried retentates were placed under nitrogen and then weighed. The
fatty acid profile of each sample was quantified by GC-MS after derivatization into fatty acid
methyl esters using ecanoic acid (C17:0) as the internal standard.
The results (data not shown) ted that microwave assisted extraction
was best
for removal of the polar lipids in the first extraction step, and somewhat less effective for
separation of l lipids. Electronic heating is more consistent in extraction effectiveness.
The final yield is comparable n microwave assisted extraction and electronic heating
assisted extraction, but, microwave assisted extraction is significantly faster.
Example 2
Protein extraction from algal biomass
(1) Acid Leaching: Algal biomass was soaked in water at pH 4.5 for 1 hour. The
s were then centrifuged at 3000 rpm for three minutes, and the supernatant d.
The remaining solids were washed 3 times with dilute acid (pH 4.5) and freeze dried.
(2) Alkaline extraction: Algal biomass was soaked in water at pH 11 for 1 hour.
following the addition of pH-adjusted water. The s were then centrifuged at 3000
for three minutes, and the supernatant removed. The supernatant
was neutralized with acid (pH
4.5) following the centrifugation. The remaining solids were washed 3 times with dilute acid
(pH 4.5) and freeze dried.
The results of acid leaching and alkaline extraction are shown below in Table 4.
W0 2012/138438
LIME!
Process Protein Yield Protein Purity
(% weight) (% weight of
protein yield)
Alkaline tion 16 45
Acid Leaching 70 32.5
Protein yield was calculated on a weight basis, comparing the weight of the freeze
dried solids to the weight of the algal biomass prior to soaking in pH-adjusted
water. Protein
purity was determined by the Official Method of the American Oil Chemists' Society (Ba-2a-
38), ing the amount of nitrogen in the freeze dried solids of each process As proteins
are an important product that adds to the value of algal product extraction, this information
allows for the use of feedstocks with varying levels of protein in the
systems and methods
disclosed herein.
Example 3
Extraction of ns from Saltwater Algal Biomass
The saltwater algal culture lly made
up of about 1—10% w/w solids in saltwater
was heated to 50°C and ined at this temperature for 1 hr. The resulting slurry was
fuged to separate the liquid phase from the solid phase. The liquid extract was
determined to be rich in globulin proteins (about 10% of the total proteins
present in the
original algal biomass).
The solids were then suspended in fiesh water and heated to about 50°C and
maintained for about 1 hour. The resulting slurry was centrifuged again to
separate the liquid
from the solid phase. The liquid phase was determined to be rich in albumin
proteins (about
% of the total proteins present in the original algal biomass).
The solids were then suspended in ethanol to achieve a 70% w/w e. This
e was heated to about 75°C and maintained at that temperature for about 1 hour. The
resulting slurry was centrifuged to separate the liquid from the solid phase The liquid phase
was determined to be rich in albumin proteins (about 30% of the total proteins present in the
original biomass).
The solids were then suspended in alkali solution (aqueous NaOH, pH 9) and heated
to about 50°C and maintained at that temperature for about 1 hour. The resulting slurry
centrifuged to separate the liquid from the solid phase. The liquid phase was determined to be
rich in glutelin proteins (about 50% of the total proteins present in the original biomass).
Example 4
Step Fractionation and Extraction of Algal Biomass by Ethanol
One thousand pounds ofNaimochloropsz's biomass (cultured from strain 202.0,
ed from Arizona State University, Laboratory for Algae Research and Biotechnology,
ATCC Deposit Number PTA-l 1048), was harvested and dewatered until algae comprised
about 35% w/w and then finally frozen.
The extraction steps were performed in a 400 gallon jacketed kettle with hinged
lids. The lids were tied down with straps and sealed with silicone. The
system also contained a
mixer with a 2 horsepower explosion proofmotor with a two blade shaft. The frozen algae
al was emptied into the tank and an equal weight of l
was pumped in using a
pneumatic drum pump. The material was stirred for 15 minutes and the jacket heated with
steam to obtain the desired ature at each extraction step. The desired
temperature is
near, meaning within 3°C of the boiling point of the mixture, but not boiling. This desired
temperature is different at each extraction step as the boiling point ofthe e changes as
the tion of ethanol is changed. Upon reaching the desired
temperature, the system was
d continuously held at the desired temperature for 60 minutes to
ensure that the contents
ofthe kettle were uniformly heated.
{0220] The contents of the kettle were then pumped out of the extraction vessel and into
Sharples decanter centrifuge, using a tic Viking vane pump at about 1 gallon per
minute. The decanter centrifuge rotor speed was set to about 6000
rpm. The solids were
collected in an ed plastic drum and consisted of about 50% w/w solids
to s. These
solids were returned to the kettle, where the aforementioned extraction
steps were repeated.
The liquid stream from the decanter was collected into a feed tank
was and then fed to the
membrane filtration system. The membrane used was a 0.375 ft2 SS ne manufactured
by Graver Technologies. The operating ions were 60°C i 5°C and with an
average
W0 2012/138438 PCT/U52012/027537
pressure gradient of 40 psi. The membrane system was backwashed about every 15 minutes
with compressed air to maintain the flux. The permeate collected from the ne
system
was free of any particulate matter. The retentate was collected and recycled to the decanter.
This extraction and fractionation is due to the change in polarity of the solvent
through the process in each extraction. in the extraction shown in F1G. 13, the process began
with about 1000 lbs. ofwet algal biomass containing about 65%
pure water (35% w/w algal
solids). This was mixed with 860 lbs. of denatured ethanol (95% ethanol and 5% methanol),
resulting in a mixture containing about 55% aqueous l. The solids and liquids were
separated using a decanter as described above. The wet solid portion weighed 525 lbs. and was
40% dry mass. A total of 525 lbs. of 95% the denatured ethanol was added to the solids,
ing in a mixture made up of about 85% aqueous ethanol. The solids and liquids were
separated using a decanter as described above. The solid portion weighed 354.5 lbs. and was
40% dry mass. To this mass, r 700 lbs. of denatured ethanol was added, resulting in
mixture of about 95% aqueous ethanol. The solids and liquids were separated using
a decanter
as described above. The resulting solids were about 40% dry mass. This biomass requires
60% less energy to dry, ated based on the latent heat ofwater and ethanol.
In some experiments (data not shown) other types of denatured ethanol
were tried.
Denatured l containing 95% ethanol and 5% isopropyl alcohol
was used in an extraction,
but was found not to be as effective as 95% ethanol and 5% methanol. Use of 100% ethanol is
a preferred ment of the present ion, but is generally not available due to cost
constraints.
The permeate stream from the membrane system was evaporated using
an in-house
fabricated batch still. The operating conditions were about 80°C during the
vacuum distillation.
All of the ethanol in the permeate was evaporated. These extraction
steps were repeated three
times, resulting in four product pools, as shown in . This is because with each
extraction step, the polarity d with the addition of water to the mixture, allowing for the
extraction of ent ents with each step. t 1 contained the algal proteins, and
as a result, retained excess water in the system that could not be vaporized under the operating
conditions. Product 2 contained the polar lipids. Product 3 ned the neutral lipids.
Finally, Product 4 was the residual biomass, containing potential coproducts such as
carotenoids.
W0 2012/138438
Example 5
Dewatering and tion of Algal Biomass by Ethanol
Upon harvesting, algal biomass typically contains n about 0.1 to 0.5 %
(w/w) solids. This can be dewatered using any of the methods known in the algae industry,
including, but not limited to membrane filtration, centrifugation, heating, sedimentation or
flotation. Flocculation can either assist in flotation or sedimentation. The typical result of such
methods is an algae slurry containing about 10% w/w solids. To dewater further, another
dewatering method may be used to remove some of the remaining free water to get the
concentration of solids closer to 40% w/w. r, the cost of ring increases
exponentially after the first dewatering is carried out. An advantage of the s and
s disclosed herein is that the allow for the extraction and fractionation of
an algal mass
that has undergone only one round of dewatering.
An example of such a process might be that in the first extraction round, following
the protocol described in Example 3, 1000 lbs. of wet biomass containing 90%
pure water and
is mixed with 1000 lbs. of denatured ethanol (95% EtOH and 5% MeOH), ing in
a solvent
mixture of about 50% aqueous ethanol. The resulting biomass (350 lbs.) is 40% dry. The
solvent composition of these wet solids is 50%
aqueous ethanol. With another 350 lbs. of
denatured l, the composition of the mixture would be about 81%
aqueous ethanol. The
resulting biomass (235 lbs.) is 40% dry. The solvent composition of these wet solids is 81%
aqueous ethanol. With another 470 lbs. of denatured ethanol, the composition of the mixture
would be about 95% aqueous ethanol. The resulting solids would be 40% dry with about 95%
ethanol. This wet biomass requires 60% less energy to dry based on the latent heat of
water
and ethanol. In this case, 100 lbs. of algae would have been extracted using 1820 lbs. ethanol.
When compared with e 3, wherein the starting material
was 40% algal solids, 350 lbs.
ofthe dry algae equivalent was extracted with 2085 lbs. ethanol.
PCT/U52012/027537
nces
The following references are herein incorporated by reference in their entirety:
US. Patent 7,148,366
Rhodes, Science Progress, 92(1):39—90, 2009. Generic review on using algae to produce
biodieselChisti, Y. . Biodiesel from lgae. Biotechnol Adv 25, 294-306. -
Generic review on using algae to produce biodiesel
Amin, Energy Convers. Manage, 4—1840, 2009. Generic review on using algae to
produce biofuel and gas
Catchpole et al., J. of Supercritical Fluids, 47:591—597, 2009. SCF C02 based extraction of
specialty lipids
Bligh E G & Dyer W J. A rapid method of total lipid extraction and purification. Can. J.
Biochem. Physiol. 37: 911-917, 1959.
Christie, W. W., Lipid Analysis, 3rd ed., Oily Press, Bridgewarer, UK, 2003, 416.
Approved Methods of the AACC, 9th ed, American Association of Cereal Chemists. St. Paul,
MN, 1995 AACC Method 58-19.
Claims (3)
1. A method of isolating chlorophylls and omega-3 rich oil from algae, comprising: a. dewatering substantially intact algal cells to make an algal s; b. adding a first ethanol fraction to the algal biomass in a ratio of about 1 part ethanol to about 1 part algal biomass by weight; c. separating a first substantially solid biomass fraction from a first substantially liquid fraction comprising proteins; d. combining the first substantially solid biomass fraction with a second ethanol fraction in a ratio of about 1 part ethanol to about 1 part solids by weight; e. separating a second substantially solid biomass on from a second substantially liquid fraction comprising polar lipids; f. combining the second substantially solid biomass fraction with a third ethanol solvent fraction in a ratio of about 1 part l to about 1 part substantially solid biomass by weight; g. ting a third substantially solid biomass on from a third substantially liquid fraction comprising neutral , including omega-3 fatty acids, carotenoids, and chlorophyll, wherein the third substantially solid biomass fraction comprises carbohydrates; and h. isolating at least one of noids, chlorophyll, and omega-3 fatty acids from the third substantially liquid fraction.
2. The method of claim 1, further comprising esterifying the neutral lipids with a catalyst in the presence of an l, and separating a water soluble fraction comprising glycerin from a water insoluble on comprising fuel esters.
3. The method of claim 2, further comprising distilling the fuel esters under vacuum to obtain a C16 or shorter fuel ester fraction, a C16 or longer fuel ester fraction, and a residue comprising omega-3 fatty acids. . The method of claim 3, further comprising deoxygenating the C16 or shorter filel ester fraction to obtain a jet fuel blend stock and/or the C16 or longer fuel on to obtain a diesel blend stock. . The method of any one of the preceding claims, wherein the isolating is carried out by adsorption with an adsorbent material. . The method of claim 5, wherein the isolating is carried out by tion with a clay. . The method of claim 6, wherein the clay is selected from the following group consisting ofbleaching clay, bentonite, and fuller’s earth. . The method of claim 1, substantially as herein described with reference to any one of the es and/or
Applications Claiming Priority (7)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US13/081,221 | 2011-04-06 | ||
US13/081,221 US8084038B2 (en) | 2010-04-06 | 2011-04-06 | Methods of and systems for isolating nutraceutical products from algae |
US13/149,595 | 2011-05-31 | ||
US13/149,595 US8115022B2 (en) | 2010-04-06 | 2011-05-31 | Methods of producing biofuels, chlorophylls and carotenoids |
US13/274,201 | 2011-10-14 | ||
US13/274,201 US8242296B2 (en) | 2010-04-06 | 2011-10-14 | Products from step-wise extraction of algal biomasses |
PCT/US2012/027537 WO2012138438A1 (en) | 2011-04-06 | 2012-03-02 | Methods of producing biofuels, chlorophylls and carotenoids |
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Publication Number | Publication Date |
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NZ615225A true NZ615225A (en) | 2015-11-27 |
NZ615225B2 NZ615225B2 (en) | 2016-03-01 |
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SG193373A1 (en) | 2013-10-30 |
BR112013025609A2 (en) | 2016-12-27 |
KR20140010972A (en) | 2014-01-27 |
CA2829481A1 (en) | 2012-10-11 |
EP2675877A1 (en) | 2013-12-25 |
CN103492541A (en) | 2014-01-01 |
WO2012138438A1 (en) | 2012-10-11 |
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