Process Technology Research, Energy Systems Division, Argonne National Laboratory, Argonne, IL 60439, USA.
Bioresour Technol. 2010 Jul;101(14):5444-8. doi: 10.1016/j.biortech.2010.02.039. Epub 2010 Mar 4.
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.
酒糟和可溶物（DGS）是玉米干法乙醇生产的主要副产物，由 30%的蛋白质和 30-40%的多糖组成。我们报告了一种用食品级生物基溶剂（乳酸乙酯、d-柠檬烯和蒸馏甲酯）同时提取蛋白质和酶解 DGS 中葡聚糖的策略。这种方法将生产出高价值的动物饲料，同时生产出更多的用于乙醇生产的糖。蛋白质提取的初步实验结果表明，蛋白质的回收率为 15-45%，疏水性生物基溶剂获得的效果最好。水解和提取的综合实验表明，生物基溶剂的添加并没有抑制纤维素的水解。然而，只有 25-33%的总蛋白质从 DGS 中被提取出来，并且提取的蛋白质主要存在于水相而不是溶剂相。我们假设由于传质不良，疏水性溶剂无法进入被 DGS 纤维结构内的水相包围的蛋白质。需要进一步的工艺改进来克服这一障碍。
