A METHOD FOR PROCESSING RAW PLANT MATERIAL, ESPECIALLY LEGUMES INTO PTOTEIN HAVING A NUTRITIONAL AND FEED VALUE, BIOETHANOL, BIOGAS AND FERTILISER MATERIALS

Abstract

A method for processing raw plant material, especially legumes into protein having a nu-tritional and feed value, bioethanol, biogas and fertiliser materials characterised in that the raw plant material is subjected to a dehusking process, followed by the dehusked raw material being crushed and subjected to extraction with stirring, wherein the insoluble solid fraction is separated and subjected to enzymatic hydrolysis using liquefying and saccharifying enzymes, then subjected to ethanol fermentation, where the produced ethanol is distilled and the digestate is transferred as a substrate for biogas production, and the liquid fraction after the extraction process is subjected to a process of precipitation to a solid form in the form of protein precipitate, which is washed with extraction buffer, after which the liquid residue is removed and subjected to a biogasification process.

Claims

1. Method of processing raw plant material, especially legumes into protein having a nutritional and feed value, bioethanol, biogas and fertiliser materials, consisting in separating raw material in the form of husks, grinding the seed residues, extracting protein to a liquid phase, separating the solid phase and subjecting it to enzymatic hydrolysis, microbial fermentation and biogasification, characterised in that the raw plant material is dehusked, the resulting husks are subjected to hydrolysis and biogasification using the CSTR method, followed by the dehusked material being milled to a fraction with a size of 0.1 to 3 mm and extracted with stirring for 1 to 12 h at 20 to 80° C., at pH 6 to 10 in excess extraction buffer at a range of 3 to 15 times the weight of the plant feedstock, wherein the insoluble solid fraction is separated and subjected to enzymatic hydrolysis with liquefying and saccharifying enzymes, followed by ethanol fermentation at a temperature of 25 to 40° C. for 24 to 72 h at pH 4 to 8, where the produced ethanol is distilled and the digestate is transferred as a substrate for biogas production, and the liquid fraction after the extraction process is subjected to a process of precipitation for 1 to 24 h at a temperature of 0 to 30° C., pH 2 to 6 into a solid in the form of a protein precipitate, which is washed with an extraction buffer with a pH 4 to 8 in a solid fraction : buffer mass ratio of 1:2, after which the liquid residue is removed, which is subjected to a biogasification process using the CSTR method, and the wet precipitate produced after biogasification is used as a fertiliser or formed into dry pellets and used as an organic fertiliser.

2. The method according to claim 1 characterised in that the solid form in the form of a protein sludge after the precipitation process is washed several times with an extraction buffer of pH 4 to 8 in a mass ratio of solid fraction: buffer 1: 2.

3. The method according to claim 1 characterised in that the solid form in the form of a protein sludge after the precipitation process is washed with an aqueous solution with an organic solvent and dried to obtain the dry fraction.

4. The method according to claim 3 characterised in that the solid form in the form of a protein sludge after the precipitation process is washed with an aqueous solution with ethanol at a concentration of 30 to 90%, pH 4 to 8, at a mass ratio of solid fraction: solution of 1: 2.

5. The method according to claim 1 characterised in that the solid form in the form of a protein sludge after the precipitation process is washed with an aqueous solution with 30 to 90% isopropanol at pH 4 to 8 in a mass ratio of solid fraction: solution of 1: 2.

Description

[0011] The method according to the invention allows for processing raw plant material, especially legumes, into pure forms of protein having a nutritional and feed value while making use of the resulting by-product streams. The method according to the invention is zero-waste, as it is carried out in a closed cycle, where the waste produced in the process is used to produce bioethanol, biogas and fertiliser materials.

EMBODIMENT I

[0012] In the embodiment, the method for processing legumes into protein having a nutritional and feed value, bioethanol, biogas and fertiliser materials involves removing the husks, milling the dehusked seeds, extracting the protein into an aqueous solvent, precipitating the protein, washing the protein with an aqueous solution, washing the protein with a solvent solution, drying the protein, and subjecting the residue to ethanol fermentation and biogasification. The raw material in the form of pulses is subjected to a dehusking process, where the resulting husks are subjected to hydrolysis and biogasification using the CSTR (Continuous Stirred Tank Reactor) method. The CSTR method involves a continuous process of residue biogasification in a bioreactor to which there is added a medium in the form of waste and a consortium of anaerobic bacteria that transform the available carbon into methane (biogas). The dehusked material is mechanically milled to a fraction with a size of 0.1 mm, suspended in extraction buffer pH 9 at a feedstock to buffer ratio of 1:10 by weight and is extracted for 1 h at 40° C. with stirring. The insoluble fraction is separated from the soluble fraction and hydrolysed using enzymes into monosaccharides, followed by ethanol fermentation, where the resulting ethanol is distilled and the digestate is transferred as a substrate for biogas production. In the soluble fraction, the pH is adjusted to 4.0, the temperature is lowered to 4° C., and the precipitation process is carried out for 4 h. The protein precipitate formed during the process is separated from the liquid phase and washed once with water pH 4 in a wet protein : water ratio of 1:2, washed subsequently with a 30% ethanol solution pH 4 in a wet protein : water ratio of 1:2 and dried. The liquid fraction is biogasified by CSTR, and the wet precipitate produced after biogasification is used as a fertiliser or formed into dry pellets and used as an organic fertiliser.

EMBODIMENT II

[0013] In the embodiment, the method for processing legumes into protein having a nutritional and feed value, bioethanol, biogas and fertiliser materials involves removing the husks, milling the dehusked seeds, extracting the protein into an aqueous solvent, precipitating the protein, washing the protein, drying the protein and subjecting the residue to ethanol fermentation and biogasification. The raw material in the form of legumes is subjected to a dehusking process, where the resulting husks are subjected to hydrolysis and biogasification using the CSTR (Continuous Stirred Tank Reactor) method. The CSTR method involves a continuous process of residue biogasification in a bioreactor to which there is added a medium in the form of waste and a consortium of anaerobic bacteria that transform the available carbon into methane (biogas). The dehusked material is mechanically milled to a fraction with a size of 2 mm, suspended in extraction buffer pH 8 at a feedstock to buffer ratio of 1:10 by weight and is extracted for 1 h at 40° C. with stirring. The insoluble fraction is separated from the soluble fraction and hydrolysed using enzymes into monosaccharides, followed by ethanol fermentation, where the resulting ethanol is distilled and the digestate is transferred as a substrate for biogas production. In the soluble fraction, the pH is adjusted 4.0, the temperature is lowered to 4° C., and the precipitation process is carried out for 4 h. The resulting protein precipitate is separated from the liquid phase and washed with water pH 7 in a wet protein : water ratio of 1:2 and dried. The liquid fraction is biogasified by CSTR, and the wet precipitate produced after biogasification is used as a fertiliser or formed into dry pellets and used as an organic fertiliser.

EMBODIMENT III

[0014] In the embodiment, the method for processing legumes into protein having a nutritional and feed value, bioethanol, biogas and fertiliser materials involves removing the husks, milling the dehusked seeds, extracting the protein into an aqueous solvent, precipitating the protein, washing the protein with an aqueous solution, washing the protein with a solvent solution, drying the protein, and subjecting the residue to ethanol fermentation and biogasification. The raw material in the form of pulses is subjected to a dehusking process, where the resulting husks are subjected to hydrolysis and biogasification using the CSTR method. The dehusked material is mechanically milled to a fraction with a size of 0.5 mm, suspended in extraction buffer pH 8 at a feedstock to buffer ratio of 1:15 by weight and is extracted for 12 h at 20° C. with stirring. The insoluble fraction is separated from the soluble fraction and hydrolysed using enzymes into monosaccharides, followed by ethanol fermentation, where the resulting ethanol is distilled and the digestate is transferred as a substrate for biogas production. In the soluble fraction, the pH is adjusted to 5.0, the temperature is lowered to 10° C. and the precipitation process is conducted for 24 h, the protein precipitate formed during the process is separated from the liquid phase and washed twice with water pH 6 in a wet protein : water ratio of 1:3, washed subsequently with a 10% isopropanol solution pH 7 in a wet protein : water ratio of 1: 1 and dried. The liquid fraction is biogasified by CSTR, and the wet precipitate produced after biogasification is used as a fertiliser or formed into dry pellets and used as an organic fertiliser.

EMBODIMENT IV

[0015] In the embodiment, the method for processing legumes into protein having a nutritional and feed value, bioethanol, biogas and fertiliser materials involves removing the husks, milling the dehusked seeds, extracting the protein into an aqueous solvent, precipitating the protein, washing the protein with an aqueous solution, washing the protein with a solvent solution, drying the protein, and subjecting the residue to ethanol fermentation and biogasification. The raw material in the form of pulses is subjected to a dehusking process, where the resulting husks are subjected to hydrolysis and biogasification using the CSTR method. The dehusked material is mechanically milled to a fraction with a size of 3 mm, suspended in extraction buffer pH 6 at a feedstock to buffer ratio of 1: 4 by weight and is extracted for 1 h at 80° C. with stirring. The insoluble fraction is separated from the soluble fraction and hydrolysed using enzymes into monosaccharides, followed by ethanol fermentation, where the resulting ethanol is distilled and the digestate is transferred as a substrate for biogas production. In the soluble fraction, the pH is adjusted to 2.0, the temperature is lowered to 30° C., and the precipitation process is carried out for 12 h. The protein precipitate obtained is separated from the liquid phase and washed four times with water pH 5 in a wet protein : water ratio of 1:5, washed subsequently with a 10% ethanol solution pH 7 in a wet protein : water ratio of 1:2 and dried. The liquid fraction is biogasified by CSTR, and the wet precipitate produced after biogasification is used as a fertiliser or formed into dry pellets and used as an organic fertiliser.

EMBODIMENT V

[0016] In the embodiment, the method for processing legumes into protein having a nutritional and feed value, bioethanol, biogas and fertiliser materials involves removing the husks, milling the dehusked seeds, extracting the protein into an aqueous solvent, precipitating the protein, washing the protein with an aqueous solution, washing the protein with a solvent solution, drying the protein, and subjecting the residue to ethanol fermentation and biogasification. The raw material in the form of pulses is subjected to a dehusking process, where the resulting husks are subjected to hydrolysis and biogasi-fication using the CSTR method. The dehusked material is mechanically milled to a fraction with a size of 0.2 mm, suspended in extraction buffer pH 7 at a feedstock to buffer ratio of 1:10 by weight and is extracted for 1 h at 40° C. with stirring. The insoluble fraction is separated from the soluble fraction and hydrolysed using enzymes into monosaccharides, followed by ethanol fermentation, where the resulting ethanol is distilled and the digestate is transferred as a substrate for biogas production. In the soluble fraction, the pH is adjusted to 5.0, the temperature is lowered to 10° C., and the precipitation process is carried out for 24 h. The resulting protein precipitate is separated from the liquid phase and washed twice with water pH 4 in a wet protein : water ratio of 1:2 and dried. The liquid fraction is biogasified by CSTR, and the wet precipitate produced after biogasification is used as a fertiliser or formed into dry pellets and used as an organic fertiliser.

EMBODIMENT VI

[0017] In the embodiment, the method for processing legumes into protein having a nutritional and feed value, bioethanol, biogas and fertiliser materials involves removing the husks, milling the dehusked seeds, extracting the protein into an aqueous solvent, precipitating the protein, washing the protein with an aqueous solution, washing the protein with a solvent solution, drying the protein, and subjecting the residue to ethanol fermentation and biogasification. The raw material in the form of pulses is subjected to a dehusking process, where the resulting husks are subjected to hydrolysis and biogasification using the CSTR method. The dehusked material is mechanically milled to a fraction with a size of 1 mm, suspended in extraction buffer pH 10 at a feedstock to buffer ratio of 1: 3 by weight and is extracted for 6 h at 50° C. with stirring. The insoluble fraction is separated from the soluble fraction and hydrolysed using enzymes into monosaccharides, followed by ethanol fermentation, where the resulting ethanol is distilled and the digestate is transferred as a substrate for biogas production. In the soluble fraction, the pH is adjusted to 2.0, the temperature is lowered to 0° C. and the precipitation process is conducted for 1 h, the protein precipitate formed during the process is separated from the liquid phase and washed once with water pH 8 in a wet protein : water ratio of 1:5, washed subsequently with a 90% ethanol solution pH 4 in a wet protein : water ratio of 1: 1 and dried. The liquid fraction is biogasified by CSTR, and the wet precipitate produced after biogasification is used as a fertiliser or formed into dry pellets and used as an organic fertiliser.

EMBODIMENT VII

[0018] In the embodiment, the method for processing legumes into protein having a nutritional and feed value, bioethanol, biogas and fertiliser materials involves removing the husks, milling the dehusked seeds, extracting the protein into an aqueous solvent, precipitating the protein, washing the protein with an aqueous solution, washing the protein with a solvent solution, drying the protein, and subjecting the residue to ethanol fermentation and biogasification. The raw material in the form of pulses is subjected to a dehusking process, where the resulting husks are subjected to hydrolysis and biogasi-fication using the CSTR method. The dehusked material is mechanically milled to a fraction with a size of 0,1 mm, suspended in extraction buffer pH 9 at a feedstock to buffer ratio of 1:10 by weight and is extracted for 2 h at 40° C. with stirring. The insoluble fraction is separated from the soluble fraction and hydrolysed using enzymes into monosaccharides, followed by ethanol fermentation, where the resulting ethanol is distilled and the digestate is transferred as a substrate for biogas production. In the soluble fraction, the pH is adjusted to 4.0, the temperature is lowered to 0° C., and the precipitation process is carried out for 24 h. The resulting protein precipitate is separated from the liquid phase and washed with a 40% ethanol solution pH 4 in a wet protein : solution mass ratio 1:2 and dried. The liquid fraction is biogasified by CSTR, and the wet precipitate produced after biogasification is used as a fertiliser or formed into dry pellets and used as an organic fertiliser.

EMBODIMENT VIII

[0019] In the embodiment, the method for processing legumes into protein having a nutritional and feed value, bioethanol, biogas and fertiliser materials involves removing the husks, milling the dehusked seeds, extracting the protein into an aqueous solvent, precipitating the protein, washing the protein with an aqueous solution, washing the protein with a solvent solution, drying the protein, and subjecting the residue to ethanol fermentation and biogasification. The raw material in the form of pulses is subjected to a dehusking process, where the resulting husks are subjected to hydrolysis and biogasification using the CSTR method. The dehusked material is mechanically milled to a fraction with a size of 2 mm, suspended in extraction buffer pH 7 at a feedstock to buffer ratio of 1: 5 by weight and is extracted for 8 h at 20° C. with stirring. The insoluble fraction is separated from the soluble fraction and hydrolysed using enzymes into monosaccharides, followed by ethanol fermentation, where the resulting ethanol is distilled and the digestate is transferred as a substrate for biogas production. In the soluble fraction, the pH is adjusted to 2.0, the temperature is lowered to 10° C., and the precipitation process is carried out for 12 h. The protein precipitate obtained is separated from the liquid phase and washed three times with water pH 5 in a wet protein : water mass ratio of 1:5, washed subsequently with a 90 % isopropanol solution pH 4 in a wet protein : water mass ratio of 1: 2 and dried. The liquid fraction is biogasified by CSTR, and the wet precipitate produced after biogasification is used as a fertiliser or formed into dry pellets and used as an organic fertiliser.

EMBODIMENT IX

[0020] In the embodiment, the method for processing legumes into protein having a nutritional and feed value, bioethanol, biogas and fertiliser materials involves removing the husks, milling the dehusked seeds, extracting the protein into an aqueous solvent, precipitating the protein, washing the protein with an aqueous solution, washing the protein with a solvent solution, drying the protein, and subjecting the residue to ethanol fermentation and biogasification. The raw material in the form of pulses is subjected to a dehusking process, where the resulting husks are subjected to hydrolysis and biogasi-fication using the CSTR method. The dehusked material is mechanically milled to a fraction with a size of 0.1 mm, suspended in extraction buffer pH 10 at a feedstock to buffer ratio of 1: 15 by weight and is extracted for 1 h at 80° C. with stirring. The insoluble fraction is separated from the soluble fraction and hydrolysed using enzymes into monosaccharides, followed by ethanol fermentation, where the resulting ethanol is distilled and the digestate is transferred as a substrate for biogas production. In the soluble fraction, the pH is adjusted to 6.0, the temperature is lowered to 0° C., and the precipitation process is carried out for 1 h. The resulting protein precipitate is separated from the liquid phase and washed with a 60% isopropanol solution pH 8 in a wet protein : solution mass ratio 1:2 and dried. The liquid fraction is biogasified by CSTR, and the wet precipitate produced after biogasification is used as a fertiliser or formed into dry pellets and used as an organic fertiliser.

EMBODIMENT X

[0021] In the embodiment, the method for processing legumes into protein having a nutritional and feed value, bioethanol, biogas and fertiliser materials involves removing the husks, milling the dehusked seeds, extracting the protein into an aqueous solvent, precipitating the protein, washing the protein with an aqueous solution, washing the protein with a solvent solution, drying the protein, and subjecting the residue to ethanol fermentation and biogasification. The raw material in the form of pulses is subjected to a dehusking process, where the resulting husks are subjected to hydrolysis and biogasi-fication using the CSTR method. The dehusked material is mechanically milled to a fraction with a size of 2 mm, suspended in extraction buffer pH 8 at a feedstock to buffer ratio of 1: 8 by weight and is extracted for 2 h at 30° C. with stirring. The insoluble fraction is separated from the soluble fraction and hydrolysed using enzymes into monosaccharides, followed by ethanol fermentation, where the resulting ethanol is distilled and the digestate is transferred as a substrate for biogas production. In the soluble fraction, the pH is adjusted to 3.0, the temperature is lowered to 20° C., and the precipitation process is carried out for 8 h. The protein precipitate obtained is separated from the liquid phase and washed three times with water pH 5 in a wet protein : water mass ratio of 1:3, washed subsequently with a 40% isopropanol solution pH 5 in a wet protein : water mass ratio of 1: 2 and dried. The liquid fraction is biogasified by CSTR, and the wet precipitate produced after biogasification is used as a fertiliser or formed into dry pellets and used as an organic fertiliser.