RU2388812C1 - Method for extraction of lipids from biomass - Google Patents

Abstract

FIELD: biotechnologies. ^ SUBSTANCE: method consists in extraction of lipid fraction from Chlorella microalgae biomass. Cell membranes of Chlorella microalgae are destroyed in device that develops vortex electromagnetic field with chaotically moving ferromagnetic particles that affect raw materials. Produced suspension of biomass is exposed to extraction with organic dissolvent by application of pulse-cavitation effect in rotor pulse-cavitation device. ^ EFFECT: production of lipid fraction from biomass of microalgae with higher yield and its further application as raw material for biodiesel fuel. ^ 1 tbl, 3 ex

Description

The invention relates to the expansion of the raw material base of alternative fuels, as well as to the processing of biomass containing, along with other biologically active substances, simple and complex lipids, more specifically, to extract from the biomass microalgae Chlorella lipid fraction as a raw material for producing components of biodiesel fuel, which is an alternative replacement commercial petroleum diesel fuel.

A known method of extracting a lipid fraction (vegetable oil) from vegetable biomass, which consists in pressing oilseeds [Paronyan V.Kh. Technology of fats and fat substitutes. - M .: DeLi print, 2006. - 760 p.]. However, the use of vegetable oils for technical purposes is impractical, since they are valuable food. In addition, the yield of oilseeds is relatively small, with one hectare of sunflower seeds you can get up to 925 liters of oil (raw materials for biofuel production), rapeseed gives 1190 liters of oil. The amount of oil that some types of algae can give, including microalgae of the genus Chlorella, reaches 95,000 liters. A known method of extracting biologically active substances, which consists in sequential processing of Chlorella biomass, which allows to isolate products of lipid and protein nature from it [Patent RU 2044770 C1, C12N 1/12, C12P 21/00, A23J 3/20, A23K 1/00, 1992]. The specified method includes pre-treatment of algae with an organic solvent (a mixture of ethanol and extraction gasoline to obtain the maximum yield of the lipid-pigment complex), separation of the complex, enzymatic hydrolysis of the fat-free residue, followed by boiling to deactivate the enzymes, separation of the aqueous phase containing the protein hydrolyzate, and non-hydrolyzable biomass residue. The disadvantage of this method is the absence of any method of destruction of the dense cell wall, preventing deeper extraction of the lipid fraction. The main methods of destruction of cell walls include the effects of ultrasonic vibrations, low and high temperatures, osmotic shock, as well as mechanical destruction of cells (grinding, grinding, crushing, homogenization, etc.). Mechanical and physical methods require high energy consumption [Patent RU 2256700 C1, C12N 1/12, A23K 1/00, A23J 3/20, C12H 1/00 // (C12N 1/12, C12R 1:89), 2004]. None of these methods provides destruction of the membranes of all cells of the microalgae of the genus Chlorella that are under the influence, since, unlike other types of microalgae, they possess (with minimal sizes) very strong cell membranes.

Closest to the claimed is a method of obtaining a complex of biologically active substances by destroying the raw materials (cell membranes) by freezing twice [Patent RU 2256700 C1, C12N 1/12, A23K 1/00, A23J 3/20, C12H 1/00 // (C12N 1 / 12, C12R 1:89), 2004].

The main disadvantages of this method are the high energy consumption and the production of a whole complex of compounds, which, in addition to lipids (fats), also includes proteins, carbohydrates, amino acids, etc., which does not allow using it as a raw material for biodiesel production. In addition, at the extraction stage, simple sedimentation is provided, which does not allow to achieve a large depth of extraction of biologically active substances, including lipids.

The objective of the invention is to develop a method for extracting the lipid fraction with a higher yield of microalgae of the genus Chlorella from the biomass for the purpose of further use to produce biodiesel fuel.

The solution of this problem is achieved by the fact that the biomass of Chlorella microalgae is subjected to physical action in the apparatus of the vortex layer ABC-100 with modifications that create a rotating electromagnetic field with randomly moving ferromagnetic particles acting on the raw material, resulting in the destruction of cell membranes, while the degree of fragmentation of cell shells reaches 99.8%. An inductor with three windings (having the same number of turns) is used, the axes of which are mutually shifted by an angle of 120 °. Equal in amplitude values, but shifted by a quarter of the period (90 °) sinusoidal currents, which excite an alternating electromagnetic field in the windings, are passed through the windings. During one period, the electromagnetic field of the inductor rotates 360 °: there is a continuous and uniform change in the direction of the magnetic field in time. The speed of rotation of the magnetic field in time is 30 s ^{-1 the} magnitude of the magnetic induction of 0.13 Tesla. Steel cylinders with a diameter of 1 mm and a length of 13 mm are used as ferromagnetic particles. The ratio between ferromagnetic particles and feed material is 3: 5. Ferromagnetic particles are enclosed in a reaction chamber, limited by grids that impede their exit during discharge of the biomass suspension. The resulting biomass suspension is then subjected to extraction with an organic solvent (nefras-C 2-70 / 85, chloroform, carbon tetrachloride) with impulse-cavitation effects in a rotary pulse-cavitation apparatus, the principle of which is based on the unsteadiness of the flows of matter, energy and momentum [Patent RU 2317142 C1, B01F 7/28, 2006]. The processed fluid, when moving through the apparatus, undergoes a multifactorial effect, consisting in pressure pulsations and its flow velocity, developed turbulence, intense cavitation, pressure pulsations in its local volumes. With the passage of the suspension of raw materials through the channels of the rotor and stator and the working chamber, the effective extraction of the lipid fraction occurs.

The method of obtaining raw materials is as follows. As raw materials, biomass of microalgae of the genus Chlorella obtained by cultivation in a nutrient medium depleted in nitrogen (nitrogen content up to 0.001 mol / l) is used. Most preferred are the pyrenic-free species of Chlorella protothecoides and Chlorella minutissima, the main reserve product of which are lipids, the content of which can reach 68% (wt.) In the cell. Chemical analysis of lipid products showed the content of the following substances: hydrocarbons - 0.04%, glycolipids - 0.9%, free fatty acids - 1.06%. The main component of the lipid fraction (up to 98%) is a mixture of triacylglycerols of higher aliphatic acids and phosphates of diacylglycerols of higher aliphatic acids, which are raw materials for the production of biodiesel. The acids that make up tri- and diacylglycerols were converted to a convenient form for chromatography. Chromatographic analysis made it possible to determine the fatty acid composition of the lipid fraction. In accordance with the analysis data, glycerin is esterified mainly with oleic, linoleic and stearic acids (Table 1).

Table 1 The content of acids in the lipid-pigment complex Acid name Content% Oleic acid 68.3 Stearic acid 3.2 Linoleic acid 25.1 Linolenic acid 1.3 Arachidonic acid 1.8 Other acids 0.3

Upon reaching a cell density of 60-65 million cells in 1 ml, Chlorella is separated from the liquid phase and sent to a crushing apparatus. After crushing the cell membranes, the raw materials are subjected to extraction in a rotary pulse cavitation apparatus. Organic solvents (nefras-C 2-70 / 85, chloroform, carbon tetrachloride) are used as extractant. The extracting ability of the listed solvents for the studied biomass is not the same.

Example 1

Title Mass g Exit, % Biomass one hundred - Nefras-S 2-70 / 85 260 - Lipid fraction - 92

Example 2

Title Mass g Exit, % Biomass one hundred - Chloroform 260 - Lipid fraction - 87

Example 3

Title Mass g Exit, % Biomass one hundred - Carbon tetrachloride 260 - Lipid fraction - 85

In this case, extraction occurs, along with the target product (lipid fraction), of minor amounts of the following lipid compounds: glycolipids, carbohydrates and carotenoids. 92% of the lipids contained in the cell pass into the extract. After extraction is completed, the extract is separated from the non-fat biomass, for example, by centrifugation. The separated extract is a solution of tri- and diacylglycerols in an organic solvent, which, after distillation of the organic solvent, enters the reactor, where the chemical process for the synthesis of biodiesel components is carried out. The lipid yield after separation of the organic solvent is 90%. Fat-free biomass contains a mixture of shell residues and cellular protein in an easily digestible form, which can be used as a protein feed additive.

The proposed method for producing raw materials for biodiesel allows maximum extraction of the lipid fraction from the biomass of microalgae, which will allow to obtain alternative fuel from non-food raw materials.

Claims (1)

A method for extracting lipids from biomass, which involves the destruction of cell membranes of microalgae of the genus Chlorella followed by extraction of the lipid fraction, characterized in that the destruction of cell membranes is carried out in a vortex electromagnetic field by ferromagnetic particles, and the extraction of the lipid fraction is carried out by an organic solvent with impulse-cavitation effects.