METHOD FOR THE SIMULTANEOUS PRODUCTION OF ETHANOL AND A FERMENTED, SOLID PRODUCT

Abstract

The invention relates to a method for the simultaneous production of a fermented, solid product and ethanol comprising the following steps: 1) providing a mixture of milled or flaked or otherwise disintegrated biomass, comprising oligosaccharides and/or polysaccharides and live yeast in a dry matter ratio of from 2:1 to 100:1, and water; 2) fermenting the mixture resulting from step (1) under conditions where the water content in the initial mixture does not exceed 65% by weight, for 1-36 hours at a temperature of about 25-60° C. under anaerobic conditions; 3) incubating the fermented mixture resulting from step (2) for 0.5-240 minutes at a temperature of about 70-150° C.; and 4) separating wet fermented, solid product from the fermented mixture resulting from step (3); further comprising either a) that the fermentation in step (2) is performed in one or more interconnected paddle worm or continuous worm conveyers with inlet means for the fermentation mixture and additives and outlet means for the ferment as well as control means for rotation speed, temperature and pH, or b) that one or more processing aids are added in any of steps (1), (2) and (3) and further comprising a step of 5) separating crude ethanol from the fermented mixture in step (2) by vacuum and/or in step (3) by vacuum or by injection of steam and condensing the surplus stripping steam. The invention further relates to the products of this method as well as uses thereof.

Claims

1.-25. (canceled)

26. A method for the simultaneous production of a fermented, solid product and ethanol comprising: providing an initial mixture of milled or flaked or otherwise disintegrated biomass, comprising oligosaccharides and/or polysaccharides, and live yeast in a dry matter ratio of from 2:1 to 100:1, and water, wherein the water content in the initial mixture does not exceed 65% by weight of the initial mixture; fermenting the initial mixture for 1-36 hours at a temperature of about 25-60 ° C. under anaerobic conditions to obtain a fermented mixture; separating wet fermented, solid product from the fermented mixture; and separating crude ethanol from the fermented mixture; wherein: (a) the fermenting step is performed in one or more interconnected paddle worm or continuous worm conveyers with inlets for the fermentation mixture and additives, an outlet for the ferment, and controls for rotation speed, temperature and pH, or (b) one or more processing aids are added prior to the fermenting step, and optionally in the fermenting step.

27. The method according to claim 26, wherein the fermenting step is performed in one or more interconnected paddle worm or continuous worm conveyers with inlets for the fermentation mixture and additives, an outlet for the ferment, and controls for rotation speed, temperature and pH.

28. The method according to claim 27, wherein one or more processing aids are added prior to the fermenting step and/or in the fermenting step.

29. The method according to claim 26, wherein one or more processing aids are added prior to the fermenting step, and optionally in the fermenting step.

30. The method according to claim 29, wherein the fermenting step is performed in a vertical screw mixer or one or more interconnected paddle worm or continuous worm conveyers with inlets for the fermentation mixture and additives, an outlet for the ferment, and controls for rotation speed, temperature and pH.

31. The method according to claim 26, wherein the one or more interconnected paddle worm or continuous worm conveyers is arranged non-vertically.

32. The method according to claim 26, wherein at least one of the one or more processing aids is an enzyme selected from the group consisting of a protease, peptidase, a-galactosidase, amylase, glucanase, pectinase, hemicellulase, phytase, lipase, phospholipase and oxido-reductase, and wherein an enzymatic saccharification process converting said oligosaccharides and/or polysaccharides into fermentable carbohydrates takes place in the fermenting step.

33. The method according to claim 26, wherein at least one of the one or more processing aids is a plant-based component selected from the group consisting of rosemary, thyme, oregano, flavonoids, phenolic acids, saponins and α- and β-acids from hops.

34. The method according to claim 32, wherein at least one of the one or more processing aids is α-galactosidase.

35. The method according to claim 26, further comprising, after the fermenting step: further fermenting the mixture resulting from the fermenting step for 1-36 hours at a temperature of about 25-60 ° C. under aerobic conditions, and optionally separating crude ethanol from the fermented mixture thereby obtained.

36. The method according to claim 26, where the continuous worm conveyer is a modified type of a single bladed or multi bladed Archimedean screw or intersected screw, designed to transport the fermenting mixture in a non-vertical direction and at the same time lifting the material so that it is transported and agitated without compacting it.

37. The method according to claim 26, wherein the live yeast is selected from the group consisting of Saccharomyces cerevisiae strains, spent brewer's yeast, spent distiller's yeast, spent yeast from wine production, and yeast strains fermenting C5 sugars.

38. The method according to claim 26, where the biomass comprising oligosaccharides and/or polysaccharides further comprises proteins originating from proteinaceous plant parts of a plant selected from the group consisting of soy, pea, lupine, and/or cereals.

39. The method according to claim 38, where said biomass comprises proteins originating from wheat.

40. The method according to claim 26, where the biomass comprising oligosaccharides and/or polysaccharides and optionally proteins further comprises oils and fats from seeds of oil bearing plants.

41. The method according to claim 40, where said biomass comprises oils and fats from rapeseed.

42. The method according to claim 26, performed as a batch, fed-batch or continuous process.

43. The method according to claim 26, wherein the fermenting step is performed under conditions where the water content in the initial mixture does not exceed 60%.

44. The method according to claim 26, wherein the fermenting step is performed under conditions where the water content in the initial mixture does not exceed 55%.

45. The method according to claim 26, wherein the fermenting step is performed under conditions where the water content in the initial mixture does not exceed 50%.

46. The method according to claim 26, wherein the fermenting step is performed under conditions where the water content in the initial mixture does not exceed 45%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0077] In one embodiment of the method of the invention in its first aspect one or more processing aids are added in any of the steps (1), (2) and (3).

[0078] In one embodiments of the method of the inventions in its second aspect the fermentation in step (2) is performed in one or more interconnected paddle worm or continuous worm conveyers, optionally arranged vertically, with inlet means for the fermentation mixture and additives and outlet means for the ferment as well as control means for rotation speed, temperature and pH, and/or further comprising a step (5) of separating crude ethanol from the fermented mixture in step (2) by vacuum and/or in step (3) by vacuum or by injection of steam and condensing the surplus stripping steam.

[0079] In one embodiment the methods of the invention further comprise a step of [0080] 2a) fermenting the mixture resulting from step (2) for 1-36 hours at a temperature of about 25-60° C. under aerobic conditions and optionally separating crude ethanol from the fermented mixture in step (2a) by vacuum.

[0081] In another embodiment step (3) is carried out at a temperature of about 70-120° C. Generally, in the incubation step (3) a high temperature is used for short time, and lower temperatures are used for longer incubation times.

[0082] The dry matter content may vary from 35 to 70% by weight of the mixture of step 1), e.g. from 40 to 65% or from 45 to 60% or from 50 to 55%.

[0083] In embodiments of both aspects of the method of the invention the at least one processing aids added in any of steps (1), (2), (2a) and (3) is one or more enzymes, and an enzymatic saccharification process converting the oligo- and/or polysaccharides into fermentable carbohydrates takes place simultaneously with the yeast fermentation. The enzyme(s) may be selected from the group consisting of protease(s), peptidase(s), galactosidase(s), amylase(s), pectinase(s), cellulase(s), hemicellulase(s), glucanase(s), glucosidase(s), phytase(s), lipase(s), oxido-reductase(s) and phospholipase(s).

[0084] This embodiment has been found to be most advantageous from an investment point of view as well as with a view to shorten reaction time. Thus, by continuously fermenting the liberated fermentable sugars, catabolite repression is avoided and the mass balance equilibrium pushed to the right.

[0085] This is of particular importance when operating at the high dry matter content according to the invention.

[0086] In other embodiments of both aspects of the method of the invention the at least one processing aids is one or more plant-based component, such as a component selected from rosemary, thyme, oregano, flavonoids, phenolic acids, saponins and α- and β-acids from hops for the modulation of soluble carbohydrates, e.g. α-lupulic acid.

[0087] The yeast to be used in the method of the invention may e.g. be selected among Saccharomyces cerevisiae strains, including spent brewer's yeast and spent distiller's yeast and spent yeast from wine production, as well as yeast strains fermenting C5 sugars. C5 sugars are pentose-based sugars, such as xylose and arabinose.

[0088] In another embodiment biomass comprising oligosaccharides and/or polysaccharides further comprises proteins originating from proteinaceous plant parts, e.g. pulses, such as soy, pea, lupine, and/or cereals, such as wheat. An example of a suitable biomass is ground or flaked, defatted soybeans. A suitable biomass can also be ground or flaked cereals e.g. wheat. Furthermore, mixtures of pulse parts and cereals are suitable biomass for processing by the method.

[0089] The biomass comprising oligosaccharides and/or polysaccharides and optionally proteins may further comprise oils and fats, e.g. from seeds of oil bearing plants, e.g. rape seed. An example of a suitable biomass is ground or flaked, full fat soybeans or rapeseeds or their mixtures.

[0090] The separation of fermented product and ethanol in steps (4) and (5) may be performed by standard unit operations comprising e.g. stripping with steam, evaporation, condensation, distillation, filtration, centrifugation and sedimentation.

[0091] In other embodiments separated compounds may be subject to special treatments comprising e.g. purification, drying, milling and admixture of other ingredients. All the unit operations that can be used for this as well as for the separation in steps (4) and (5) are well known to a person skilled in the art.

[0092] The separated fermented, solid product may subsequently be made more water-soluble by hydrolysis, e.g. by enzymes.

[0093] The method of the invention may e.g. be performed as a batch, fed-batch or continuous process.

[0094] Finally, the ethanol produced by the process of the invention may be used to generate heat for the process e.g. by catalytic combustion and thus at the same time get rid of polluting volatile organic compounds, e.g. hexane. In this case the by-products generated will be carbon dioxide and water.

[0095] In one embodiment the fermented, solid product of the invention comprises protein in an amount of 25-90% by weight on dry matter basis, and glyceride in an amount of 0-30% by weight on dry matter basis. About 1-35% relative of said protein may be originating from yeast protein and about 65-99% relative of said protein may be originating from proteinaceous plant parts, e.g. from pulses and/or cereal, such as soybeans and/or wheat.

[0096] In another embodiment the fermented, solid product is derived from biomass predominantly comprising oligosaccharides and/or polysaccharides and comprises yeast protein in an amount of 1-95% by weight on dry matter basis and carbohydrate in an amount of 5-99% by weight on dry matter basis.

[0097] The crude ethanol obtainable according to the invention can be used for the generation of heat for the fermentation process.

[0098] The invention also relates to the use of a fermented, solid product according to the invention in a processed food product for human and/or animal consumption; as an ingredient to be used in a food or feed product; or as an ingredient of a cosmetic or a pharmaceutical product or a nutritional supplement.

[0099] Finally the invention relates to a food, feed, cosmetic or pharmaceutical product or a nutritional supplement containing from 1 to 99% by weight of a fermented, solid product according to the invention.

EXAMPLES

Example 1

[0100] Fermentation in a Continuous Process of a Biomass Comprising Polysaccharides and Proteins from Pulses

[0101] In the following the fermentation of a biomass based on defatted soy is illustrated.

[0102] 100 kg per hour of dehulled and defatted, flash desolventised soy flakes were continuously fed to a closed single bladed worm conveyer able to transport, lift and mix the material (bioreactor). At the same time water and slurry of spent brewer's yeast (10% dry matter) where added in an amount to reach a dry matter content of 40% by weight in the mixture.

[0103] In the bioreactor the resulting slurry was incubated for 8 hours at 34° C.

[0104] Next, the slurry was heated in a second incubator (bioreactor) to 100° C. with injection of a surplus of life steam for approx. 30 min. The surplus steam containing volatile organic compounds (VOC's) comprising ethanol was transferred to a cooling heat exchanger.

[0105] The resulting condensate had an ethanol concentration of 15% by weight. The ethanol yield was 4.8kg per 100kg of soy flakes.

[0106] Subsequently, the wet solid product was flash dried and milled at an Alpine pin mill.

[0107] The dried product had the following analysis:

TABLE-US-00001 Crude Protein (N × 6.25) 58.3% Carbohydrates 24.0% Moisture 5.6% Crude fat 0.9% Crude fiber 4.2% Ash 7.0%

[0108] Furthermore, anti-nutritional factors in the dried, fermented product were significantly reduced vs. the raw material content:

TABLE-US-00002 Fermented Product Raw Material Oligosaccharides 0.9% 13.5% Trypsin Inhibitor 2,900 TIU/g 62,000 TIU/g β-conglycinin 8 ppm 90,000 ppm

[0109] The fermented product is highly nutritious and palatable and thus suitable as an ingredient in a number of food and feed products.

Example 2

[0110] Composition of VOC's in Exhaust Drying Air of a Fermented Biomass Comprising Polysaccharides and Proteins

[0111] In the following the content of volatile organic compounds (VOC's) in the drying air from a fermented biomass based on defatted soy is illustrated. An air amount of two liter was collected at a temperature of 55.7° C. and a relative humidity of 67.1% in a Tedlarbag.

[0112] Analytical Methods:

[0113] GC/FID—refers to a method where the sample from the Tedlarbag was analyzed by GC analysis and quantified vs. Ethanol using a FID detector.

[0114] GC/MS—refers to a method where the sample components from the Tedlarbag are first adsorbed in a tube containing an adsorbent material followed by desorbtion for GC analysis by heating, and quantified by the recording of peak area vs. Toluen-d.sub.6. The identification was done by comparison of the mass spectra with a NIST-database.

[0115] The results are tabulated in the following:

TABLE-US-00003 Component CAS-nr Content mg/m.sup.3 Analytical method Ethanol 64-17-5 1,300 GC/FID 2-Methyl-pentane 107-83-5 0.103 GC/MS 3-methyl-pentane 96-14-0 0.085 GC/MS Ethyl acetate 141-78-6 0.261 GC/MS Hexane 110-54-3 0.109 GC/MS 2-Methyl-1-propanol 78-83-1 0.139 GC/MS 3-Methyl-1-butanol 123-51-3 1.082 GC/MS 2-Methyl-1-butanol 137-32-6 0.511 GC/MS Hexanal 66-25-1 0.046 GC/MS The analytical values are mean values of two determinations

[0116] From the listed components it can be an option to use the bio ethanol obtained by the process to generate heat for the process e.g. by catalytic combustion, and at the same time get rid of polluting volatile organic compounds e.g. hexane.

Example 3

[0117] Fermentation in a Batch Process of a Biomass Comprising Polysaccharides and Proteins From a Mixture of Pulses and Cereals Added Various Enzymes as Processing Aid

[0118] In the following the fermentation of a biomass based on a mixture of defatted soy and wheat is illustrated.

[0119] 300 kg of a mixture containing 10% by weight of dry matter of crushed wheat and 90% by weight of dry matter of dehulled and defatted, flash desolventised soy flakes were fed to a closed single bladed worm conveyer able to transport, lift and mix the material (bioreactor). At the same time water and a slurry of spent brewer's yeast (10% dry matter) and enzymes where added in an amount to reach a dry matter content of 45% by weight in the mixture.

[0120] The fermenting mixture had a content of 3.5% by weight of yeast based on total dry matter and 0.4% by weight based on dry matter of each of Viscozyme Wheat, Spirizyme Fuel and Liquozyme from Novozymes, which enzymes provide alfa-amylase, glucoamylase, beta-glucanase activities and side activities in the form of xylanase and cellulase activities.

[0121] In the bioreactor the resulting slurry was transported, mixed and incubated for 18 hours at 34° C.

[0122] The ethanol content in the ferment was 73.1 g/kg dry matter corresponding to 7.3 kg per 100 kg dry matter of the wheat/soy mixture.

[0123] The wet solid product was flash dried and milled at an Alpine pin mill.

[0124] The dried fermented product had a water content of 6.6% by weight and a protein content of 59A % by weight.

Example 4

[0125] Fermentation in a Laboratory Scale Process of a Biomass Comprising Polysaccharides and Proteins From Soy, Added β-lupulic Acid from Hop as Processing Aid

[0126] The fermentation was performed on a biomass based on a mixture of defatted soy and 3.5% by weight of yeast and water added in an amount to reach a dry matter content of 48% by weight in the mixture.

[0127] To the fermentation mixtures β-lupulic acid from hop was added in various concentrations.

[0128] The fermentation was performed in small glass containers at 34° C. for 17 hours followed by heat treatment to stop the fermentation.

[0129] After the fermentation was terminated the content of soluble carbohydrates was extracted by stirring a watery suspension slurry of 10% DM for 30 min followed by centrifugation for 10 min at 3000×g.

[0130] The watery extracts of the ferment was analyzed for carbohydrate content by the phenol-sulphuric acid method (Carbohydrate analysis—A practical approach; IRL Press, Oxford. Ed. M. F. Chaplan & J. F. Kenndy, 1986).

[0131] The results obtained are tabulated in the following:

TABLE-US-00004 β-lupulic acid Soluble carbohydrates Concentration in ppm mg/ml in extract 0 7.9 75 7.7 1500 7.4 3000 7.1

[0132] The crude ethanol was not isolated in this experiment. However, the crude ethanol might have been separated from the fermented mixture by conventional methods, and the concentration of ethanol in the resulting condensate determined by conventional methods, e.g. as described in example 1.

[0133] From the results it can be seen that the use of β-lupulic acid as processing aid reduce the content of water-soluble carbohydrates in the fermented product i.e. it improve the fermentation process.

Example 5

[0134] Fermentation in a Batch Process of a Biomass Comprising Polysaccharides and Proteins from Soy, Added Various Hop Based Processing Aids

[0135] 250 kg of dehulled and defatted, flash desolventised soy flakes were fed to a closed single bladed worm conveyer able to transport, lift and mix the material (bioreactor). At the same time water and a slurry of spent brewer's yeast (10% dry matter) and hop based processing aids where added in an amount to reach a dry matter content of 45% by weight in the mixture.

[0136] The fermenting mixture had a content of 3.5% by weight of yeast based on total dry matter and 3000 ppm of α-, or β-acids, or α+β acids, or iso-a-acids from hop.

[0137] In the bioreactor the resulting slurry was transported, mixed and incubated for 16 hours at 34° C.

[0138] The wet solid product was flash dried and milled at an Alpine pin mill. The dried fermented products had a water content of 4.5-5.3% by weight and a protein content of 56.0-56.8% by weight.

[0139] Before and after the fermentation was terminated the content of soluble carbohydrates was analyzed on watery extracts of the ferment and on the dried product by the method described in Example 4.

[0140] As mentioned in example 4 the crude ethanol was not isolated in this experiment either. However, the crude ethanol might have been separated from the fermented mixture by conventional methods, and the concentration of ethanol in the resulting condensate determined by conventional methods, e.g. as described in example 1.

[0141] The results obtained are tabulated in the following:

TABLE-US-00005 Soluble Soluble Soluble Soluble Type of carbohydrates carbohydrates carbohydrates carbohydrates processing Main Before After Reduction in mg/ml In an extract of aid added constituents fermentation fermentation and in % relative the dried product None — 15.4 7.4 8.0-51.9% 8.3 Hop CO.sub.2- β - acids 13.4 5.5 7.9-59.0% 6.3 extract Hop pellets α + β - acids 13.6 7.4 6.2-45.6% 7.8 Hop EtOH- α + β - acids 18.1 10.1 8.0-44.2% 9.3 extract Hop iso- K salt of 13.1 5.1 8.0-61.1% 5.2 extract iso-α- acids

[0142] From the results it can be seen that by the use of various hop components during fermentation it is possible to modulate the amount of soluble carbohydrates.

[0143] The presence of a hop extract where the main constituent is β-acids as well as an extract where the main constituent is iso-a-acids reduced the content of soluble carbohydrates, whereas the combined presence of α- and β-acids tend to preserve the content of soluble carbohydrates relative to the reference without any addition of hop processing aids.

[0144] As mentioned in example 4 the crude ethanol was not isolated in this experiment as well. However, the crude ethanol might have been separated from the fermented mixture by conventional methods, and the concentration of ethanol in the resulting condensate determined by conventional methods, e.g. as described in example 1.