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In situ detoxification of dry dilute acid pretreated corn stover by co-culture of xylose-utilizing and inhibitor-tolerant Saccharomyces cerevisiae increases ethanol production

Zhu, Jia-Qing, Li, Xia, Qin, Lei, Li, Wen-Chao, Li, Hui-Ze, Li, Bing-Zhi, Yuan, Ying-Jin
Bioresource technology 2016 v.218 pp. 380-387
Saccharomyces cerevisiae, biomass, coculture, corn stover, ethanol, ethanol production, fermentation, glucose, saccharification, xylose
Co-culture of xylose-utilizing and inhibitor-tolerant Saccharomyces cerevisiae was developed for bioethanol production from undetoxified pretreated biomass in simultaneously saccharification and co-fermentation (SSCF) process. Glucose accumulation during late fermentation phase in SSCF using xylose-utilizing strain can be eliminated by the introduction of inhibitor-tolerant strain. Effect of different ratios of two strains was investigated and xylose-utilizing strain to inhibitor-tolerant strain ratio of 10:1 (w/w) showed the best xylose consumption and the highest ethanol yield. Inoculating of xylose-utilizing strain at the later stage of SSCF (24–48h) exhibited lower ethanol yield than inoculating at early stage (the beginning 0–12h), probably due to the reduced enzymatic efficiency caused by the unconsumed xylose and oligomeric sugars. Co-culture SSCF increased ethanol concentration by 21.2% and 41.0% comparing to SSCF using individual inhibitor-tolerant and xylose-utilizing strain (increased from 48.5 and 41.7g/L to 58.8g/L), respectively, which suggest this co-culture system was very promising.