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Simultaneous saccharification and co-fermentation of corn stover pretreated by H2O2 oxidative degradation for ethanol production

Liu, Lu, Zhang, Zhicai, Wang, Jia, Fan, Yajuan, Shi, Wenjing, Liu, Xiaocui, Shun, Quanshan
Energy 2019 v.168 pp. 946-952
Candida tropicalis, Saccharomyces cerevisiae, cell growth, corn stover, ethanol, ethanol production, fermentation, glucose, hydrogen peroxide, models, pH, saccharification, temperature, xylose
The simultaneous saccharification and co-fermentation of Saccharomyces cerevisiae and Candida tropicalis for ethanol production using H2O2-pretreated corn stover (CS) were performed in 250-mL or 500-mL Erlenmeyer flasks at various S. cerevisiae-C. tropicalis ratios (4:1, 3:1, 2:1, 1:1, 1:2, 1:3 and 1:4), fermentation temperatures (32 °C, 35 °C and 38 °C), inoculation ratios (8%, 12% and 16%), initial pH values (4.5, 5 and 5.5) and fermentation times (96 h, 120 h and 144 h). The optimum S. cerevisiae-C. tropicalis ratio derived from mono-factor design test was 3:1. According to orthogonal design experiment results, the optimum fermentation temperature, inoculation ratio, initial pH and fermentation time with a dry solid substrate content of 25% were 32 °C 12%, 5.0 and 144 h, respectively, and the maximum ethanol concentration was 10.924 g/100 mL. The cell growth, ethanol production and total substrate consumption in the process of simultaneous saccharification and co-fermentation conformed to logistical model, Luedeking-Piret model and general substrate consumption law of mono-strain fermentation, respectively. Collectively, S. cerevisiae and C. tropicalis simultaneously produced ethanol from xylose and glucose without interference, respectively.