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Assessing solid digestate from anaerobic digestion as feedstock for ethanol production
- Teater, Charles, Yue, Zhengbo, MacLellan, James, Liu, Yan, Liao, Wei
- Bioresource technology 2011 v.102 no.2 pp. 1856-1862
- Panicum virgatum, alkalis, anaerobic digesters, anaerobic digestion, biorefining, cellulose, corn stover, energy crops, enzymatic hydrolysis, ethanol, ethanol production, feedstocks, fermentation, glucose, hydrolysates, sodium hydroxide, tanks
- Ethanol production using solid digestate (AD fiber) from a completely stirred tank reactor (CSTR) anaerobic digester was assessed comparing to an energy crop of switchgrass, and an agricultural residue of corn stover. A complete random design was fulfilled to optimize the reaction conditions of dilute alkali pretreatment. The most effective dilute alkali pretreatment conditions for raw CSTR AD fiber were 2% sodium hydroxide, 130°C, and 3h. Under these pretreatment conditions, the cellulose concentration of the AD fiber was increased from 34% to 48%. Enzymatic hydrolysis of 10% (dry basis) pretreated AD fiber produced 49.8g/L glucose, while utilizing 62.6% of the raw cellulose in the AD fiber. The ethanol fermentation on the hydrolysate had an 80.3% ethanol yield. The cellulose utilization efficiencies determined that the CSTR AD fiber was a suitable biorefining feedstock compared to switchgrass and corn stover.