Protein Recovery

Abstract

A process for recovering a protein-containing fermentation agent, comprising (i) forming an aqueous mixture of an organic material and a protein-containing fermentation agent capable of fermenting the organic material to produce ethanol, (ii) fermenting the aqueous mixture to produce ethanol, (iii) recovering from the fermented aqueous mixture an ethanol stream which is rich in ethanol and a co-product stream comprising unfermented organic material, fermentation agent and an aqueous solution of dissolved solids in water, (iv) subjecting the co-product stream to a first separation stage to recover a first stream rich in the unfermented organic material and a second stream rich in the fermentation agent suspended in the aqueous solution, and (v) subjecting the second stream to a second separation step, capable of recovering suspended solids from a liquid, to recover a third stream rich in the fermentation agent and a fourth stream rich in the aqueous solution. The invention also relates to a new yeast composition obtainable from the process.

1 . A process for recovering a protein-containing fermentation agent, comprising:
 (i) forming an aqueous mixture of an organic material and a protein-containing fermentation agent capable of fermenting the organic material to produce ethanol;   (ii) fermenting the aqueous mixture to produce ethanol;   (iii) recovering from the fermented aqueous mixture an ethanol stream which is rich in ethanol and a co-product stream comprising unfermented organic material, fermentation agent and an aqueous solution of dissolved solids in water;   (iv) subjecting the co-product stream to a first separation stage to recover a first stream rich in the unfermented organic material and a second stream rich in the fermentation agent suspended in the aqueous solution; and   (v) subjecting the second stream to a second separation stage, capable of recovering suspended solids from a liquid, to recover a third stream rich in the fermentation agent and a fourth stream rich in the aqueous solution.   
     
     
         2 . The process according to  claim 1 , wherein the first separation stage comprises a mechanical separation stage. 
     
     
         3 . The process according to  claim 2 , wherein the mechanical separation stage includes a decanting stage. 
     
     
         4 . The process according to  claim 1 , wherein the first separation stage includes a centrifugal separation stage. 
     
     
         5 . The process according to  claim 1 , wherein the second separation stage comprises a mechanical separation stage. 
     
     
         6 . The process according to  claim 5 , wherein the mechanical separation stage of the second separation stage includes a centrifugal separation stage. 
     
     
         7 . The process according to  claim 6 , wherein the centrifugal separation stage is carried out using a disk stack separator. 
     
     
         8 . The process according to  claim 7 , wherein the third stream is subjected to a dewatering stage. 
     
     
         9 . The process according to  claim 8 , wherein the dewatering stage comprises a mechanical dewatering stage. 
     
     
         10 . The process according to  claim 9 , wherein the mechanical dewatering stage comprises subjecting the third stream to a filter press. 
     
     
         11 . The process according to  claim 1 , further comprising drying the third stream to reduce the moisture content. 
     
     
         12 . The process according to  claim 8 , further comprising drying the third stream, after the dewatering stage, to further reduce the moisture content. 
     
     
         13 . The process according to  claim 1 , wherein the fourth stream is subjected to an evaporation stage to produce a syrup. 
     
     
         14 . The process according to  claim 1 , wherein the unfermented organic material is processed into a cake after separation from a stillage obtained from (i)-(iii). 
     
     
         15 . The process according to  claim 12 , wherein the unfermented organic material is processed into a cake after separation from a stillage obtained from (i)-(iii) and wherein syrup is sprayed onto the cake, to produce distillers dark grains and solubles (DDGS). 
     
     
         16 . The process according to  claim 1 , wherein the organic material comprises a fermentable carbohydrate. 
     
     
         17 . The process according to  claim 1 , wherein the organic material comprises a cereal grain, maize, wheat, sorghum or barley; potato; or beet molasses. 
     
     
         18 . The process according to  claim 1 , wherein the fermentation agent comprises fungal cells capable of fermenting the organic material to ethanol. 
     
     
         19 . The process according to  claim 1 , wherein the fermentation agent comprises a yeast. 
     
     
         20 . The process according to  claim 19 , wherein the yeast is a yeast of the genus  Saccharomyces.    
     
     
         21 . The process according to  claim 1 , further comprising formulating the recovered fermentation agent as a feed additive in an animal feed composition. 
     
     
         22 . The process according to  claim 21 , wherein the fermentation agent comprises less than 2 wt % of the animal feed composition. 
     
     
         23 . The process according to  claim 1 , comprising formulating the recovered fermentation agent as a protein source in a feed material in an animal feed composition. 
     
     
         24 . The process according to  claim 23 , wherein the fermentation agent comprises more than 2 wt % of the animal feed composition. 
     
     
         25 . The process according to  claim 23 , wherein the fermentation agent comprises more than 4 wt % of the animal feed composition. 
     
     
         26 . The process according to  claim 23 , wherein the fermentation agent comprises from 5 wt % to 40 wt % of the animal feed composition. 
     
     
         27 . A process for preparing an animal feed composition, comprising recovering a fermentation agent using a process according to  claim 1 , combining the fermentation agent with a carbohydrate source, and optionally an additional protein source, and optional additives, wherein the fermentation agent comprises at least 2 wt % of the animal feed composition. 
     
     
         28 . A process for treating stillage, the stillage being obtained from a fermentation process and comprising water, protein-containing fermentation agent, suspended fibrous and non-fibrous solids and dissolved solids, the process comprising: separating the majority of the suspending fibrous solids from the rest of the stillage; and then separating the majority of the protein-containing fermentation agent from the water and dissolved solids. 
     
     
         29 . An animal feed composition prepared by a process according to  claim 27 . 
     
     
         30 . The process of  claim 1  wherein producing ethanol and a protein-containing fermentation agent according to (i)-(v) is carried out in an apparatus comprising:
 (i) a fermentation stage for fermenting an aqueous mixture comprising an organic material and a fermentation agent capable of fermenting the organic material, to produce ethanol; 
 (ii) a first separation stage for recovering the ethanol from the unfermented aqueous mixture; 
 (iii) a second separation stage, downstream of the first separation stage for recovering unfermented organic material from the fermentation agent and from an aqueous solution of dissolved solids in water; and 
 (iv) a third separation stage, downstream of the second separation stage, for recovering the fermentation agent from the aqueous solution. 
 
     
     
         31 . The process according to  claim 30 , wherein the third separation stage comprises a mechanical separator. 
     
     
         32 . The process according to  claim 31 , wherein the third separation stage comprises a disk stack separator. 
     
     
         33 . The process according to  claim 30 , further a dewaterer for dewatering the recovered fermentation agent. 
     
     
         34 . The process according to  claim 33 , further comprising a drier for removing additional moisture from the recovered fermentation agent. 
     
     
         35 . The process according to  claim 30 , wherein the fermentation agent is a yeast. 
     
     
         36 . A protein-containing composition obtainable by a process according to  claim 1 . 
     
     
         37 . The protein-containing composition according to  claim 36  comprising yeast in combination with at least one non-starch polysaccharide, (NSP), wherein the yeast comprises at least 60 wt % of the composition, based on the dry weight of the composition. 
     
     
         38 . The composition according to  claim 37 , wherein the yeast comprises at least 90 wt % of the composition, based on the dry weight of the composition. 
     
     
         39 . The composition according to  claim 37 , wherein the yeast comprises at most 99.5 wt % of the composition, based on the dry weight of the composition. 
     
     
         40 . The composition according to  claim 37 , further comprising a compound selected from the group consisting of sucrose, at least one reducing sugar at least one mineral, at least one water soluble oligosaccharide, water, and combinations thereof. 
     
     
         41 - 44 . (canceled) 
     
     
         45 . The composition according to  claim 37 , wherein_the or each NSP is present in an amount up to 5 wt % of the composition. 
     
     
         46 . The composition according to  claim 37 , wherein the NSP comprises arabinoxylan, beta-glucan, galactose or a combination thereof. 
     
     
         47 . (canceled) 
     
     
         48 . The composition according to  claim 37 , wherein the NSP comprises at least 90 wt % arabinoxylan and beta-glucan. 
     
     
         49 . An animal feed composition comprising 2 to 40 wt % of the protein-containing composition according to  claim 37 . 
     
     
         50 . A method of stimulating growth in an animal comprising administering a growth stimulating amount of the composition according to  claim 36 . 
     
     
         51 . A method of stimulating growth in an animal comprising administering a growth stimulating amount of the animal feed composition according to  claim 29 . 
     
     
         52 . A method of stimulating growth in an animal comprising administering a growth stimulating amount of the composition according to  claim 37 . 
     
     
         53 . The method according to  claim 50 , wherein the animal is selected from cattle, sheep, goats, pigs, poultry, fish, crustacea, horses, cats and dogs. 
     
     
         54 - 58 . (canceled) 
     
     
         59 . The process of  claim 28 , wherein the protein-containing fermentation agent comprises yeast. 
     
     
         60 . The process of  claim 28 , wherein the process is carried out in an apparatus comprising:
 (i) a fermentation stage for fermenting an aqueous mixture comprising an organic material and a fermentation agent capable of fermenting the organic material, to produce ethanol;   (ii) a first separation stage for recovering the ethanol from the unfermented aqueous mixture;   (iii) a second separation stage, downstream of the first separation stage for recovering unfermented organic material from the fermentation agent and from an aqueous solution of dissolved solids in water; and   (iv) a third separation stage, downstream of the second separation stage, for recovering the fermentation agent from the aqueous solution.   
     
     
         61 . The process of  claim 59 , wherein the process is carried out in an apparatus comprising:
 (i) a fermentation stage for fermenting an aqueous mixture comprising an organic material and a fermentation agent capable of fermenting the organic material, to produce ethanol;   (ii) a first separation stage for recovering the ethanol from the unfermented aqueous mixture;   (iii) a second separation stage, downstream of the first separation stage for recovering unfermented organic material from the fermentation agent and from an aqueous solution of dissolved solids in water; and   (iv) a third separation stage, downstream of the second separation stage, for recovering the fermentation agent from the aqueous solution.   
     
     
         62 . A protein-containing composition obtainable by a process according to  claim 28 . 
     
     
         63 . A protein-containing composition obtainable by a process according to  claim 59 . 
     
     
         64 . The protein-containing composition according to  claim 62  comprising yeast in combination with at least one non-starch polysaccharide, (NSP), wherein the yeast comprises at least 60 wt % of the composition, based on the dry weight of the composition. 
     
     
         65 . The protein-containing composition according to  claim 63  comprising yeast in combination with at least one non-starch polysaccharide, (NSP), wherein the yeast comprises at least 60 wt % of the composition, based on the dry weight of the composition.