title: Protease digestion from wheat stillage within a dry grind ethanol facility.
abstract: As the current starch based ethanol market increases at its rapid pace, finding new markets for the primary coproduct, distiller's grains, has gained considerable interest. One possibility is to isolate the protein-rich fraction for use as precursors to biochemicals and bioplastics, further decreasing fossil fuel consumption. This research focuses on enzymatic extraction of protein peptides from wheat heavy stillage using commercially available proteases. The energy saved due to this process ranged from ∼ 1.5 to 3.0 GJ/ton wheat stillage compared to fossil fuel-based chemicals. Using Protex 6L (Genencor), ∼ 57% of the protein in the stillage was soluble 24 h after protease addition at 0.1% w/w loading. Of these proteins, ∼ 32% were already soluble, indicating the importance of using wet heavy stillage as the feedstock rather than dried distiller's grains. Peptide size was less than 6 kDa. Further improvements in protein removal may be obtained through a fed batch addition of protease and improved protease cocktails.
authors.affiliation: Biomass Conversion Research Laboratory, Michigan State University, Lansing, MI 48910, USA. balsbrya@msu.edu
authors.forename: Bryan
authors.initials: B
authors.lastname: Bals
authors.forename: Ben
authors.initials: B
authors.lastname: Brehmer
authors.forename: Bruce
authors.initials: B
authors.lastname: Dale
authors.forename: Johan
authors.initials: J
authors.lastname: Sanders
mesh_terms: D056804:Biofuels; D004736:Energy-Generating Resources; D000431:Ethanol; D008970:Molecular Weight; D010447:Peptide Hydrolases / Q000378:metabolism*; D010455:Peptides / Q000302:isolation & purification; D010940:Plant Proteins / Q000302:isolation & purification*; D014908:Triticum / Q000737:chemistry* / Q000378:metabolism
chemical_list: D056804:Biofuels; D010455:Peptides; D010940:Plant Proteins; D000431:Ethanol; D010447:Peptide Hydrolases