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Ethanol production from mixtures of Distiller’s Dried Grains with Solubles (DDGS) and corn

Li, Xiujuan, Chen, Sitong, Yu, Yang, Wang, Shengwei, Xu, Zhaoxian, Huang, He, Jin, Mingjie
Industrial crops and products 2019 v.129 pp. 59-66
cellulose, coproducts, corn, cost effectiveness, dry milling, enzymatic hydrolysis, ethanol, ethanol fermentation, ethanol production, feedstocks, hydrolysates, industry, liquids, saccharification, sugars
The dry milling ethanol industry produces Distillers’ Dried Grains with Solubles (DDGS) as major co-products, which are composed of unhydrolyzed and unfermented polymeric sugars. Ethanol fermentation with the mixture of DDGS and corn has the potential to reduce cost, further utilize sugars in the DDGS and increase overall ethanol production in current dry grind process. In the current study, DDGS was pretreated with dilute alkali, liquid hot water (LHW) and dilute acid (DA). The pretreated DDGS was enzymatically hydrolyzed at 30% (w/w) solid loading and the resulting hydrolysate was mixed with liquefied corn (30%, w/w) at different ratios (0:1, 1:5, 1:2, 1:1 and 1:0 w/w) for simultaneous saccharification and fermentation (SSF). Compared with 30% corn only, SSF with LHW treated DDGS and corn (1:1) resulted in 12.6% increase in ethanol production with 69.3% increase in cellulose conversion, while DA treated DDGS resulted in 15.1% increase in ethanol production with 86.5% increase in cellulose conversion. This work implies that sugars within DDGS can be further converted in regular corn process after appropriate pretreatment. Feedstock cost can be reduced and the overall ethanol production can be enhanced by this strategy, which is beneficial to corn ethanol production in dry-mill process.