An attempt towards simultaneous biobased solvent based extraction of proteins and enzymatic saccharification of cellulosic materials from distiller’s grains and solubles

• Published in: Bioresource technology Vol. 101; no. 14; pp. 5444 - 5448
• Main Authors: Datta, Saurav, Bals, B.D., Lin, Yupo J., Negri, M.C., Datta, R., Pasieta, L., Ahmad, Sabeen F., Moradia, Akash A., Dale, B.E., Snyder, Seth W.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.07.2010; [New York, NY]: Elsevier Ltd; Elsevier
• Subjects: AFEX; Animal Feed; ANIMAL FEEDS; BASIC BIOLOGICAL SCIENCES; Biobased solvents; Biological and medical sciences; Biotechnology; Biotechnology - methods; CELLULOSE; Cellulose - chemistry; Cyclohexenes - chemistry; Distiller’s grains and solubles (DGS); Edible Grain - chemistry; Enzymatic hydrolysis; ESTERS; ETHANOL; Ethanol - chemistry; Food industries; Fundamental and applied biological sciences. Psychology; GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; Glucose - chemistry; HYDROLYSIS; Industrial Waste; MASS TRANSFER; POLYSACCHARIDES; Polysaccharides - chemistry; PRODUCTION; Protein extraction; PROTEINS; Proteins - chemistry; Reproducibility of Results; SACCHARIDES; SACCHARIFICATION; SOLVENTS; Solvents - chemistry; Terpenes - chemistry; Time Factors; Use and upgrading of agricultural and food by-products. Biotechnology; Protein extraction; Distiller’s grains and solubles (DGS); Biobased solvents; Enzymatic hydrolysis; AFEX; Distillery by product; Enzyme; Cellulose; Solubility; Saccharification; Solvent extraction; Protein; Hydrolysis; Enzymatic digestion; Distiller's grains and solubles (DGS); Solvent
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2010.02.039

Distiller’s grains and solubles (DGS) is the major co-product of corn dry mill ethanol production, and is composed of 30% protein and 30–40% polysaccharides. We report a strategy for simultaneous extraction of protein with food-grade biobased solvents (ethyl lactate, d-limonene, and distilled methyl esters) and enzymatic saccharification of glucan in DGS. This approach would produce a high-value animal feed while simultaneously producing additional sugars for ethanol production. Preliminary experiments on protein extraction resulted in recovery of 15–45% of the protein, with hydrophobic biobased solvents obtaining the best results. The integrated hydrolysis and extraction experiments showed that biobased solvent addition did not inhibit hydrolysis of the cellulose. However, only 25–33% of the total protein was extracted from DGS, and the extracted protein largely resided in the aqueous phase, not the solvent phase. We hypothesize that the hydrophobic solvent could not access the proteins surrounded by the aqueous phase inside the fibrous structure of DGS due to poor mass transfer. Further process improvements are needed to overcome this obstacle.