GB2454766A

GB2454766A - Froth separation

Info

Publication number: GB2454766A
Application number: GB0815383A
Authority: GB
Inventors: Roy Browne
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-08-26
Filing date: 2008-08-26
Publication date: 2009-05-20
Also published as: GB0815383D0

Abstract

Disclosed are a method and corresponding apparatus in which mixture composed of two or more materials, one of which is foamable, has a gas added to it so as to form a foam fraction. The foam fraction is subsequently separated from the non foam fraction, thus separating the two materials from one another. The apparatus may feature a vessel 10 with a gas inlet port 12, headspace 18 for the foam, and conduit 16, to a first air lock 20 with a water wash, and a second air lock 22 with a solvent wash, and a pressure release valve 24. Also specified are a substantial number of different materials, mainly biological, which might be foam separated in the manner described.

Description

1 2454766

METHOD FOR THE SELECTIVE SEPARATION OF COMPONENTS

FROM A MATERIAL

Field of the Invention

The present invention relates to a method for selectively separating at least one component from a material in order to provide the at least one component in a form suitable for use, for example, in the food and green chemistry industries.

Background to the Invention

Material, in particular biological material, often comprises a number of components. Generally these components are inter-dispersed throughout the material forming a complex mixture. It is difficult to isolate one or more of the components from the material as a whole. For example, grass comprises a mixture of water, cellulose (composed of linked glucose molecules), proteins, non-structural polysaccharides, lipids, waxes, sugars, amino acids and phenolics. Blood, which is a waste product of the meat industry, is largely composed of water, protein, polar lipids, such as phospholipids, and low molecular weight metabolites. The use of components from these materials is restricted as unwanted components are inter-dispersed with components of potential value. The presence of the unwanted components can make the material unsuitable for use in food industries and other industries. However, it is difficult to separate the components of value from the unwanted components. Furthermore, the concentrations of the components of value in the material may be low such that the cost of separating the components of value from the unwanted components of the material is not economical when the components are separated using currently available extraction technologies. It would be advantageous therefore if a more efficient method of isolating components of interest from materials was available in order to allow these components to be efficiently recovered for other uses.

One example of an industry which uses a biological material is bio-ethanol production. Bio-ethanol may be produced from high cellulose biomass.

However, the production of bio-ethanol from high cellulose biomass has encountered obstacles in the form of the biochemical breakdown of the high cellulose biomass into a fermentable form and the separation and concentration of the components of the high cellulose biomass desired for use as fermentation substrates. Typical methods for the breakdown of the cellulose fraction of the high cellulose biomass to glucose units for fermentation include the use of enzymes or strong acids. However, the efficiency of these methods is limited due to the presence of lignin, waxes, lipids, proteins and other components of the biomass. Some biomass may also have unwanted antimicrobial components that may reduce the efficiency of yeast fermentation. These unwanted components can also reduce process efficiency including, for example, reducing evaporation efficiency and the formation of "gummy" residues blocking up pipes. At present, the production of bio-ethanol from high cellulose biomass is not practiced due to the cost and the limitations of the existing technology.

Current bio-ethanol production is therefore largely based on biomass that also has potential for human consumption, for example, maize and wheat.

This has raised concerns as it reduces the amount of biomass available to meet the increasing demand for food. Furthermore, even when biomass having potential for human consumption is used, for example, high starch or sugar crops, unwanted components of the biomass can reduce the efficiency of the process of bio-ethanol production and can detract from the quality of the product. Alternatively, the unwanted components are extracted using relatively expensive processes, for example, sugar processing. These unwanted components are considered waste by-products of various food/industrial processes. However, if these unwanted components could be further purified, they may be of value for other processes.

In the case of waste blood, this has a high water content. Waste blood is therefore generally dried and the remaining residue burned. This results in problems due to the smell and the amount of energy required.

Furthermore, the drying of the blood can be retarded by certain components of the blood. It would be advantageous if these components could be removed from the waste blood prior to processing in order to reduce the amount of energy required. Furthermore, it would be advantageous if components of waste blood could be recovered for use in industry.

A number of processes to separate a material into its components are known. These include the following examples.

In the process of sugar refining, lime is added with carbon dioxide in order to precipitate out a sludge to remove unwanted components, including waxes. The sludge constitutes a waste product.

Plant materials containing wax are boiled to produce a wax-rich scum.

However, this process is energy intensive and results in changes in the chemistry of the material which is boiled.

Further examples of processes to separate a material include the use of solvents in two-phase separation, and drying a material and extracting with pure solvents. Disadvantages associated with these processes include the high energy input required for drying the material and the loss of solvent as a residue. Furthermore, the use of solvents is expensive and problems arise in the handling of solvents and solvent residues.

Supercritical carbon dioxide is used as a solvent in liquid form under high pressure. However, this is limited to carbon dioxide and high pressure is required. Furthermore, high quality gas is required and processing and equipment are expensive. Supercritical carbon dioxide cannot be applied to materials in liquid aqueous solutions.

Physical separation may also be used, for example, in wheat milling.

Following the removal of bran, wheat endosperm may be used in bio-ethanol production. However, wheat endosperm comprises a complex mixture of components including both components which are useful for fermentation and unwanted components. An example of an unwanted component is phospholipids. The presence of phospholipids in the fermentation and ethanol removal process is undesirable, but the phospholipids may have uses in other industries. Accordingly, it would be advantageous if the phospholipids could be separated from the wheat endosperm.

In most processes, foaming is undesirable as it interferes with the handling and processing of materials. Foam is therefore seen as an unwanted by-product in the manufacture of various substances. In particular, foam is a serious problem in the chemical industry, especially for biochemical processes. Many biological substances, for example some proteins, easily create foam on agitation and/or aeration. Foam is a problem because it alters the liquid flow and blocks oxygen transfer from air (therefore preventing microbial respiration in aerobic fermentation processes). In brewing, foam produced by excessive foaming during the early stages of fermentation is considered a waste product. The extent of the foaming declines as the fermentation and the alcohol concentration increases. During the extraction of starch from potatoes, foaming is also seen as undesirable. Anti-foaming agents, such as silicone oils, are therefore used to reduce foaming.

Summary of invention

According to a first aspect of the present invention there is provided a method for selectively separating two or more components of a material which is capable of forming a foam upon addition of a gas, the method comprising the steps of: -adding a gas to the material to form a foam fraction and a non-foam fraction wherein each of the foam fraction and the non-foam fraction comprises at least one of the two or more components; and -separating the foam fraction from the non-foam fraction to separate the two or more components.

The inventor has surprisingly identified that foaming, which was previously considered undesirable, can be advantageous as it can be used to separate the components of a material. The separation of the components of the material allows for concentration of components of interest and for the removal of unwanted components. This makes the material more suited to subsequent processing, for example, treatment with enzymes and allows for more efficient subsequent processing of the components of the material for various uses, such as in the food or green chemistry industries. Thus, the commercial utility of materials that may otherwise be considered waste, or consigned to low value uses, is increased. Furthermore, the use of solvents, such as chloroform, is avoided and contamination of the material to be separated is reduced or prevented.

The method of the first aspect of the invention may be applied to a wide selection of materials wherein it is desired to separate the material into its components.

Typically the material is any material comprising two or more components wherein it is desirable to separate the two or more components.

In certain embodiments the material comprises at least one of the group consisting of a solid, a fluid, a liquid and a mixture thereof. In certain embodiments the material is a suspension. In alternative embodiments the material is a solution. In certain embodiments the material comprises a solid in a liquid. The solid may be a settled solid or in suspension in the liquid.

In certain embodiments the material is a biological material. Typically, the biological material is selected from the group consisting of blood, in particular waste blood, plant materials such as grass, forestry waste or high cellulose biomass, plant food stuffs such as potatoes, cereal crops, wheat, wheat endosperm, maize, root vegetables, sugar beet, sugar cane, rice and beans, and waste water, such as wash water used in potato processing, for example, by potato chip (crisp) manufacturers.

In certain embodiments the material is a non-biological material. Typically, the non-biological material is selected from the group consisting of oil, materials of mineral origin, tar, sand, molasses and waste water.

In certain embodiments the material comprises a mixture of biological and non-biological materials.

In certain embodiments the two or more components to be separated comprise at least one of starch, proteins, amino acids, fermentable sugars, low molecular weight metabolites, cellulose, lignin, waxes, lipids, phospholipids, antimicrobial components and other non-starch components.

In certain embodiments the foam fraction comprises at least one non-starch component and the non-foam fraction comprises a starch corn pon ent.

In certain embodiments the foam fraction comprises components unsuitable for fermentation, for example, phospholipids, and the non-foam fraction comprises fermentable components, for example, fermentable sugars.

In certain embodiments the foam fraction comprises lipids and proteins from, for example, potatoes. In alternative embodiments, the foam fraction comprises lipids from, for example, grass.

In certain embodiments the non-foam fraction comprises proteins.

The components of the foam fraction and the non-foam fraction will vary depend ing upon the material to be separated and the gas used. For example, when the material is grass, the foam fraction may include lipids and the non-foam fraction may include proteins, starch and amino acids.

When the material is potatoes, the foam fraction may include proteins, waxes and lipids.

In certain embodiments the gas is added as a gas in a liquid, for example, water or a water/alcohol solution. In certain embodiments the gas is added directly as a gas. In certain embodiments the gas is produced by a chemical reaction. In certain embodiments the gas is added by agitation of the material. In certain embodiments the gas is released from the material.

In certain embodiments the gas is added as a mixture of gases. In alternative embodiments the gas is added as a single type of gas.

In certain embodiments the gas is selected from the group consisting of carbon dioxide, nitrogen, nitrogen oxide, nitrogen dioxide, oxygen, methane, propane, air and mixtures thereof.

The gas may be selected depending upon the material to be separated and the desired quality of the separation of the material into the two or more components. Advantageously a wide selection of gases may be used. It is not necessary for the gas to be pressurised. A high quality gas is not necessary. Furthermore, processing costs are reduced using this method.

In certain embodiments two or more different gases are added sequentially to the material.

In certain embodiments the addition of the gas results in precipitation of one or more of the components of the material.

In certain embodiments the addition of the gas changes the chemistry of the environment of the material, for example, the acidity (pH) and/or oxidation state of the environment.

In certain embodiments the gas becomes dissolved before coming out of solution.

Without wishing to be bound by theory, it is hypothesised that when the gas comes out of solution, selective components of the material form a foam fraction with the gas wherein other components of the material remain in a non-foam fraction, thus allowing selective separation of the components of the material.

In certain embodiments the gas is passed through the material under pressure.

In certain embodiments a closed system is used. This advantageously allows for a continuous stream of controlled gas mediated foaming and extraction.

In certain embodiments the method is carried out at atmospheric pressure.

In certain embodiments the method includes one or more further steps of processing the foam fraction and/or the non-foam fraction.

The foam fraction may be processed as follows.

Typically excess liquid is allowed to drain from the foam fraction. In certain embodiments the foam fraction is passed through a conduit and the excess liquid allowed to drain back into the non-foam fraction. In certain embodiments the foam fraction is passed through one or more air locks.

In certain embodiments the foam fraction is washed using one or more washes to clean the foam. In certain embodiments the wash is a water wash. In alternative embodiments the wash is an alcohol/water wash. In certain embodiments the foam fraction is dissolved in a solvent. Typically the solvent may be an organic solvent, such as ethyl acetate. In alternative embodiments the foam fraction is frozen, milled and dried.

In certain embodiments a vacuum is used to pass the foam fraction through the one or more washes. In certain embodiments the foam fraction is passed through the one or more washes under pressure.

In certain embodiments the gas from the foam fraction is recycled. In certain embodiments wherein the gas is added as a gas in a liquid, the liquid is recycled.

In certain embodiments the foam fraction is subjected to one or more additional purification steps.

In certain embodiments the method comprises one or more further steps of adding gas to the non-foam fraction to form a further foam fraction.

This enhanced recovery of components remaining in the initial non-foam fraction.

In certain embodiments the method further comprises one or more treatment steps to assist breakdown of the material into the two or more components to be separated. Any suitable technique known to persons skilled in the art may be used to breakdown the material into the two or more components.

In certain embodiments the material is broken down physically to release the components of the material, for example, by pulping or grinding of the material.

In certain embodiments one or more enzymes are added to the material to enhance breakdown of the material into its components. Typically the one or more enzymes may be selected from the group consisting of pectinases, cellulases and mixtures thereof. In certain embodiments the one or more enzymes are added with the gas.

The enhanced breakdown of the material into its components increases the efficiency of the fractionation and separation of the components which occurs upon addition of the gas. Thus, increased purity and/or concentration of the two or more components to be separated may be achieved. Furthermore, the physical breakdown of the material enhances the activity of the one or more enzymes and may enhance foaming. In the case where the gas is acidic, for example when the gas is carbon dioxide, the activity of the one or more enzymes is further increased due to the favourable acidic pH environment.

In certain embodiments the method includes a step of treating the material prior to the addition of the gas to remove certain components, for example, by precipitation of proteins using heat or by the addition of one or more acids.

In certain embodiments the one or more acids are selected from the group consisting of acetic acid, ascorbic acid (vitamin C), citric acid, organic acids, inorganic acids and the like. In certain embodiments the one or more acids serve to reduce or prevent oxidation and/or discolouration of the material. In certain embodiments the addition of the one or more acids results in hydrolysis of the material.

The addition of the one or more acids before or at the same time as the addition of the one or more enzymes is advantageous as the acidic (low pH) environment enhances the activity of the one or more enzymes.

According to a second aspect of the present invention there is provided a method for processing a solid material in order to breakdown the solid material into two or more components, the method comprising the step of: -adding a gas to the solid material wherein addition of the gas results in dissolution of the solid material into the two or more components.

Processing the material using the method of the second aspect of the invention makes the material more suited to subsequent processing, for example, treatment with enzymes and allows for more efficient subsequent processing of the components of the material for various uses, such as in the food or green chemistry industries.

In certain embodiments dissolution of the solid material comprises liquefaction of at least one of the two components of the solid material. In certain embodiments the addition of the gas to the solid material results in formation of a suspension.

Typically the material is any solid material comprising two or more components wherein it is desirable to breakdown the material into the two or more components.

In certain embodiments the solid material is a solid material having a high moisture content. In certain embodiments the solid material is contained in a liquid. The solid may be a settled solid or in suspension in the liquid.

Typically liquefaction comprises liquefaction of the component into the moisture content of the solid material or into the carrier liquid.

In certain embodiments the material is a biological material. Typically, the biological material is selected from the group consisting of plant materials such as grass, forestry waste or high cellulose biomass, and plant food stuffs such as potatoes, cereal crops, wheat, wheat endosperm, maize, root vegetables, sugar beet, sugar cane, rice and beans.

In certain embodiments the material is a non-biological material. Typically, the non-biological material is selected from the group consisting of materials of mineral origin, tar and sand.

In certain embodiments the material comprises a mixture of a biological material and a non-biological material.

In certain embodiments the two or more components to be separated comprise at least one of starch, proteins, amino acids, fermentable sugars, low molecular weight metabolites, cellulose, lignin, lipids, waxes, phosphol ipids and other non-starch components.

In certain embodiments addition of the gas results in liquefaction of the waxes and/or the lipids.

The gas may be selected depending upon the material to be broken down and the desired quality of the breakdown of the material into the two or more components. Advantageously a wide selection of gases may be used. It is not necessary for the gas to be pressurised. A high quality gas is not necessary. Furthermore, processing costs are reduced using this method.

In certain embodiments the gas is recycled. In certain embodiments wherein the gas is added as a gas in a liquid, the liquid is recycled.

In certain embodiments the material is subjected to one or more additional purification steps.

In certain embodiments the method comprises one or more further steps of adding gas to the material to form a foam fraction and a non- foam fraction wherein each of the foam fraction and the non-foam fraction comprises at least one of the two or more components. Typically the foam fraction is separated from the non-foam fraction to separate the two or more components.

In certain embodiments the gas is passed through the material under pressure.

In certain embodiments the method is carried out at atmospheric pressure.

In certain embodiments the method further comprises one or more additional steps of treating the material to breakdown the material into the two or more components. Any suitable technique known to persons skilled in the art may be used to breakdown the material into the two or more components.

The enhanced breakdown of the material into its components increases the efficiency of the breakdown of the material into its components occurring upon addition of the gas. Thus, increased purity and/or concentration of the two or more components to be separated may be achieved. Furthermore, the physical breakdown of the material enhances the activity of the one or more enzymes and may enhance foaming. In the case where the gas comprises an acidic gas, such as carbon dioxide, the activity of the one or more enzymes is further increased due to the favourable acidic pH environment.

In certain embodiments the one or more acids is selected from the group consisting of acetic acid, ascorbic acid (vitamin C), citric acid, organic acids, inorganic acids and the like. In certain embodiments the one or more acids serve to reduce or prevent oxidation and/or discolouration of the material. In certain embodiments the addition of the one or more acids results in hydrolysis of the material.

In certain embodiments the material obtained from the method of the second aspect of the invention is further treated using the method of the first aspect of the invention.

In certain embodiments the methods of the first and second aspects of the invention are carried out simultaneously. In alternative embodiments the method of the second aspect of the invention is carried out first followed by the method of the first aspect of the invention in a two-stage process.

In certain embodiments the two-stage process is carried out using a single apparatus.

A further aspect of the invention provides for the use of the foregoing methods of the invention for the separation of starch from non-starch components in the production of starch.

A further aspect of the invention provides for the use of the foregoing methods of the invention for the separation of proteins from non-protein components.

A further aspect of the invention provides for the use of the foregoing methods of the invention for the removal of phospholipids from a material, such as wheat or waste blood. In certain embodiments the phospholipids may be processed for use in other industries, for example the bio-diesel industry.

A further aspect of the invention provides for the use of the foregoing methods of the invention for the removal of waxes from biomass in the production of alcohol, for example, bio-ethanol. Typically the methods of the invention are applied prior to fermentation.

A further aspect of the invention provides for the use of the foregoing methods of the invention for the removal of components not suitable for fermentation, such as lipids, from fermentable components of materials, such as biomass, prior to fermentation.

A further aspect of the invention provides for the use of the foregoing methods of the invention for the removal of components from waste blood prior to drying. Typically the components to be removed are components which retard burning of the waste blood. Thus, removal of these components reduces the amount of energy input required to burn the remaining blood residue.

A further aspect of the invention provides for the use of the foregoing methods of the invention for waste water treatment. Treatment of waste water using the methods of the invention allows for recovery of components of the waste water and reduces pollution and the cost of disposal of the waste water.

A further aspect of the present invention provides a purified product produced using the foregoing methods of the invention.

A yet further aspect of the present invention provides a kit for use in separating a material, said kit comprising a gas along with instructions for the use of the same.

A third aspect of the present invention relates to an apparatus for selectively separating two or more components of a material which is capable of forming a foam upon addition of a gas, the apparatus comprising: -a vessel for receipt of the material; -an inlet to the vessel for addition of a gas wherein the inlet is positioned at the bottom of the vessel; -an outlet from the vessel wherein the outlet is positioned at the top of the vessel.

In certain embodiments the apparatus is used for carrying out the methods of the invention.

In certain embodiments the outlet is positioned in the roof of the vessel. In certain embodiments the outlet is connected to a conduit. In certain embodiments the conduit extends vertically from the vessel. This allows excess liquid to drain from a foam fraction of the material formed upon addition of the gas.

Typically, the conduit is connected to one or more air locks. In certain embodiments the one or more air locks are provided with washes, for example, water washes. In certain embodiments, the one or more air locks are provided with solvent.

In certain embodiments the inlet is positioned in the base of the vessel.

In certain embodiments the apparatus is part of a closed system.

Typically, gas is recycled and re-added to the inlet.

In certain embodiments the apparatus is pressurised. In certain embodiments the system includes a pressure release valve. In certain embodiments gas is drawn through the conduit in a vacuum.

In certain embodiments the vessel includes a grinding unit to breakdown solid materials.

In certain embodiments the vessel includes a foaming space. This allows excess liquid to drain from the foam fraction of the material formed upon addition of the gas.

Embodiments of the various aspects of the invention apply mut at/s mutandis for other aspects of the invention where applicable.

Definitions Unless otherwise defined, all technical and scientific terms used herein have the meaning commonly understood by a person who is skilled in the

art in the field of the present invention.

The term "foam-fraction" is used herein to refer to a fraction of the material comprising bubbles in a liquid and/or in a solid. Typically, the foam fraction is the top fraction.

The term "non-foam fraction" is used herein to define a fraction of the material which is free, or substantially free, from bubbles. Typically, the non-foam fraction is the bottom fraction.

The term "suspension" refers herein to a fluid containing solid particles therein.

The term "solution" refers herein to a fluid containing a dissolved solute therein.

The term "dissolution" as used herein refers to the breakdown of the solid material into the two or more components, for example, by liquefaction of at least one of the two or more components to form a suspension.

The term "separation" as used herein is intended to encompass both complete and partial separation. Similarly, the term "breakdown" is intended to refer to both complete and partial breakdown of the material into its components.

Throughout the specification, unless the context demands otherwise, the terms "comprise" or "include", or variations such as "comprises" or "comprising", "includes" or "including" will be understood to imply the inclusion of a stated integer or group of integers, but not the exclusion of any other integer or group of integers.

As used herein, terms such as "a", "an" and "the" include singular and plural referents unless the context clearly demands otherwise.

Brief Description of the Figure

The invention will be more clearly understood from the following description of some embodiments thereof, given by way of example only, with reference to the following figure in which: Figure 1 shows an apparatus for carrying out the methods of the invention.

Detailed Description of the Invention

Figure 1 shows an apparatus for carrying out the method of the first aspect of the invention, either alone or in combination with the method of the second aspect of the invention.

A material 9 for processing is contained in a vessel 10. The vessel 10 is provided with an inlet 12 positioned in the base of the vessel 10 for receipt of a gas. An outlet 14 is positioned at the top of the vessel 10. The outlet 12 is connected to a conduit 16 extending vertically from the vessel 10. A foaming space 18 is left free of material 9 at the top of the vessel 10 to allow for formation of a foaming fraction. The conduit 16 is connected to two air locks 20, 22 and provided with a pressure release valve 24.

In use, a gas is added to the vessel 10 through the inlet 12 to breakdown a solid material 9 and to bring one or more components of the material 9 into solution. A grinding unit (not shown) may be provided in the vessel 10 to assist in the breakdown of the solid material. Enzymes and/or acid may also be added either in combination with the gas or separately. Addition of the gas results in formation of a foam fraction in the foaming space 18.

The foam fraction exits through the outlet 14 into the conduit 16. Excess liquid may drain from the foaming space 18 and the conduit 16 back into the remaining material. The foam fraction passes through two air locks 20, 22. The first air lock 20 is provided with a water wash to clean the foam. The second air lock 22 is provided with a solvent to dissolve the foam. The gas may be recycled back to the inlet for further treatment of the remaining material (not shown).

EXAMPLE

Example 1 -Method for Selective Separation of Components from Potatoes Whole potatoes were pulped and a cellulose-rich pulp fraction was separated from a liquid fraction using a juice extractor. The liquid fraction was stirred for 20 minutes and then allowed to settle for at least 20 minutes during which time a starch-rich sediment fraction settled. The material remaining in suspension was decanted off as supernatant.

Carbon dioxide was provided by reaction of citric acid with soda lime and carbon dioxide in water or a water/alcohol solution was added to the starch-rich sediment.

It was observed that addition of carbon dioxide in water or in the water/alcohol solution to the starch-rich fraction resulted in dissolution of non-starch components present in the starch-rich fraction allowing the non-starch components to be separated out as a solution and pure starch obtained. This therefore allows for more efficient removal of non-starch contaminants and hence cleaner starch can be obtained. Further, the amount of washing of the starch and the amount of water or water/alcohol solution required for washing is reduced. It was further observed that the addition of carbon dioxide in water or in the water/alcohol solution advantageously reduced oxidation of the material and increased the acidity of the material.

The carbon dioxide and/or the water or water/alcohol solution can be cleaned for recycling.

The decanted supernatant contained protein and low molecular weight metabolites, including sugars, amino acids and polar lipids. Proteins were removed by coagulation with heat (65 to 70°C) and filtering. The polar lipids were removed by addition of gas resulting in foaming and separation into a foam-fraction comprising the polar lipids and a non- foam fraction.

The foam-fraction was forced upwards and passed through a water wash following which the foam was dissolved in an alcohol solution.

The sugars and amino acids of the decanted supernatant are suitable for fermentation. However, the polar lipids do not act as useful substrates for fermentation and reduce the efficiency of the process causing, for example, unwanted foaming in conventional brewing. Due to their alcohol soluble nature, the polar lipids also interfere in evaporation of the alcohol during distillation for ethanol production. The removal of the polar lipids using foaming therefore advantageously separates the polar lipids from the sugars and amino acids allowing enhanced efficiency of the subsequent processing of the sugars and amino acids.

The last step may also be used to remove polar lipids from blood.

The cellulose-rich pulp fraction produced following pulping of the potatoes was suspended in solution (e.g. water or the juice fraction) and a combination of physical action and enzymes with gas in solution was used to force waxy/lipid components from the pulp fraction into solution. This produced a richer cellulose fraction which was more accessible to cellulase enzymes. Separation of the liquid solution was then carried out using gas induced foaming.

The last two steps can also be applied in the same manner to plant material, such as grass or to yield a clean cellulose fraction for potential use in industrial applications, such as the paper industry.

The invention is not limited to the embodiments herein before described which may be varied in construction, detail and process step without departing from the spirit of the invention.

Claims

Claims 1. A method for selectively separating two or more components of a material which is capable of forming a foam upon addition of a gas, the method comprising the steps of: -adding a gas to the material to form a foam fraction and a non-foam fraction wherein each of the foam fraction and the non-foam fraction comprises at least one of the two or more components; and -separating the foam fraction from the non-foam fraction to separate the two or more components.
2. A method as claimed in claim 1 wherein the material comprises at least one of the group consisting of a solid, a fluid, a liquid and a mixture thereof.
3. A method as claimed in claim 2 wherein the material comprises a liquid.
4. A method as claimed in claim 3 wherein the liquid is obtained by addition of a gas to a solid material wherein addition of the gas to the solid material results in dissolution of the solid material.
5. A method as claimed in any preceding claim wherein the material is a biological material.
6. A method as claimed in claim 5 wherein the biological material is selected from the group consisting of blood, plant materials, such as grass, forestry waste or high cellulose biomass, and plant food stuffs, such as potatoes, cereal crops, wheat, wheat endosperm, maize, root vegetables, rice and beans.
7. A method as claimed in any one of claims 1 to 4 wherein the material is a non-biological material, such as oil, molasses, materials of mineral origin and waste water.
8. A method as claimed in any preceding claim wherein the two or more components to be separated comprise at least one of starch, proteins, amino acids, fermentable sugars, low molecular weight metabolites, cellulose, lignin, lipids, waxes, phospholipids and other non-starch components.
9. A method as claimed in any preceding claim wherein the foam fraction comprises at least one non-starch component and the non-foam fraction comprises a starch component.
10. A method as claimed in any preceding claim wherein the foam fraction comprises components unsuitable for fermentation, for example, phospholipids, and the non-foam fraction comprises fermentable components, for example, fermentable sugars.
11. A method as claimed in any preceding claim wherein the gas is added as a gas in a liquid.
12. A method as claimed in one of claims 1 to 10 wherein the gas is added directly as a gas.
13. A method as claimed in any one of claims 1 to 10 wherein the gas is produced by a chemical reaction.
14. A method as claimed in any preceding claim wherein the gas comprises a mixture of gases.
15. A method as claimed in any preceding claim wherein the gas is selected from the group consisting of carbon dioxide, nitrogen, nitrogen oxide, nitrogen dioxide, oxygen, methane, propane, air and mixtures thereof.
16. A method as claimed in any preceding claim wherein the gas is passed through the material under pressure.
17. A method as claimed in any one of claims 1 to 15 wherein the method is carried out at atmospheric pressure.
18. A method as claimed in any preceding claim wherein the method includes one or more further steps of processing the foam fraction and/or the non-foam fraction.
19. A method as claimed in any preceding claim wherein excess liquid is allowed to drain from the foam fraction.
20. A method as claimed in any preceding claim wherein the foam fraction is passed through one or more air locks.
21. A method as claimed in any preceding claim wherein the foam fraction is washed using one or more washes.
22. A method as claimed in any preceding claim wherein the foam fraction is dissolved in a solvent.
23. A method as claimed in any one of claims 1 to 21 wherein the foam fraction is frozen, milled and dried.
24. A method as claimed in any one of claims 21 to 23 wherein a vacuum is used to pass the foam fraction through the one or more washes.
25. A method as claimed in any one of claims 21 to 23 wherein the foam fraction is passed through the one or more washes under pressure.
26. A method as claimed in any preceding claim wherein the gas from the foam fraction is recycled.
27. A method as claimed in any preceding claim wherein the method further includes a step of breaking down the material to release the two or more components, for example, by pulping or grinding of the material.
28. A method as claimed in any preceding claim wherein one or more enzymes are added to the material.
29. A method as claimed in any preceding claim wherein one or more acids are added to the material.
30. A method for processing a solid material in order to breakdown the solid material into two or more components, the method comprising the step of: -adding a gas to the solid material wherein addition of the gas results in dissolution of the solid material into the two or more components.
31. A method as claimed in claim 30 wherein dissolution of the solid material comprises liquefaction of at least one of the two or more components of the solid material.
32. A method as claimed in claim 31 wherein the addition of the gas to the solid material results in formation of a suspension and/or a solution.
33. A method as claimed in any one of claims 30 to 32 wherein the solid material is in a liquid.
34. A method as claimed in any one of claims 30 to 33 wherein the material is a biological material.
35. A method as claimed in claim 34 wherein the biological material is selected from the group consisting of plant materials such as grass, forestry waste or high cellulose biomass, and plant food stuffs such as potatoes, cereal crops, wheat, wheat endosperrn, maize, root vegetables, rice and beans.
36. A method as claimed in any one of claims 30 to 33 wherein the material is a non-biological material.
37. A method as claimed in any one of claims 30 to 36 wherein the two or more components to be separated comprise at least one of starch, proteins, amino acids, fermentable sugars, low molecular weight metabolites, cellulose, lignin, lipids, waxes, phospholipids and other non-starch components.
38. A method as claimed in claim 37 wherein addition of the gas results in liquefaction of the waxes and/or the lipids.
39. A method as claimed in any one of claims 30 to 38 wherein the gas is added as a gas in a liquid.
40. A method as claimed in any one of claims 30 to 38 wherein the gas is added directly as a gas.
41. A method as claimed in any one of claims 30 to 38 wherein the gas is produced by a chemical reaction.
42. A method as claimed in any one of claims 30 to 41 wherein the gas is added as a mixture of gases.
43. A method as claimed in any one of claims 30 to 42 wherein the gas is selected from the group consisting of carbon dioxide, nitrogen, nitrogen oxide, nitrogen dioxide, oxygen, methane, propane, air and mixtures thereof.
44. A method as claimed in any one of claims 30 to 43 wherein the gas is recycled.
45. A method as claimed in any one of claims 30 to 44 wherein the gas is passed through the material under pressure.
46. A method as claimed in any one of claims 30 to 44 wherein the method is carried out at atmospheric pressure.
47. A method as claimed in any one of claims 30 to 46 wherein the method further includes a step of breaking down the material to release the two or more components, for example, by pulping or grinding of the material.
48. A method as claimed in any one of claims 30 to 47 wherein one or more enzymes are added to the material.
49. A method as claimed in any one of claims 30 to 48 wherein one or more acids are added to the material.
50. A method as claimed in any one of claims 30 to 49 wherein the method comprises one or more further steps of forming a foam fraction and a non-foam fraction wherein each of the foam fraction and the non- foam fraction comprises at least one of the two or more components.
51. A method as claimed in claim 50 wherein the formation of the foam fraction and the non-foam fraction occurs simultaneously with the dissolution of the solid material into the two or more components.
52. A method as claimed in claim 50 wherein method is carried out in a two-stage process.
53. A method as claimed in claim 52 wherein the two-stage process is carried out using a single apparatus.
54. A method as claimed in any one of claims 50 to 53 wherein the foam fraction is separated from the non-foam fraction to separate the two or more components.
55. Use of the methods of any one of claims 1 to 54 for the separation of starch from non-starch components in the production of starch.
56. Use of the methods of any one of claims 1 to 54 for the separation of proteins from non-protein components.
57. Use of the methods of any one of claims 1 to 54 for the removal of lipids from wheat or blood.
58. Use of the methods of any one of claims 1 to 54 for the removal of waxes from biomass in the production of alcohol, such as bio-ethanol.
59. Use of the methods of any one of claims I to 54 for the separation of cellulose from biomass.
60. Use of the methods of any one of claims 1 to 54 for the removal of components not suitable for fermentation fermentable substrates of materials, such as biomass, prior to fermentation.
61. Use of the methods of any one of claims 1 to 54 for the removal of components from waste blood prior to drying.
62. Use of the methods of any one of claims 1 to 54 for waste water treatment.
63. A purified product produced using the methods of any one of claims 1 to 54.
64. An apparatus for selectively separating two or more components of a material which is capable of forming a foam upon addition of a gas, the apparatus comprising: -a vessel for receipt of the material; -an inlet to the vessel for addition of a gas wherein the inlet is positioned at the bottom of the vessel; -an outlet from the vessel wherein the outlet is positioned at the top of the vessel.
65. An apparatus as claimed in claim 64 wherein the outlet is connected to a conduit extending vertically from the vessel.
66. An apparatus as claimed in claim 64 or 65 wherein the conduit is connected to one or more air locks.
67. An apparatus as claimed in claim 66 wherein the one or more air locks are provided with washes.
68. An apparatus as claimed in claim 66 wherein the one or more air locks are provided with solvent.
69. An apparatus as claimed in any one of claims 64 to 68 wherein the apparatus is part of a closed system.
70. An apparatus as claimed in claim 69 wherein gas is recycled and re-added to the inlet.
71. An apparatus as claimed in any one of claims 64 to 70 wherein the apparatus is pressurised.
72. An apparatus as claimed in any one of claims 64 to 71 wherein the vessel includes a foaming space.
73. A method substantialiy as hereinbefore described with reference to the accompanying example.
74. An apparatus substantially as hereinbefore described with reference to the accompanying figure.