Assessing solid digestate from anaerobic digestion as feedstock for ethanol production.
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 3 h. 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 49.8 g/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.
Teater
Charles
C
Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, MI 48824, USA.
Yue
Zhengbo
Z
MacLellan
James
J
Liu
Yan
Y
Liao
Wei
W
D000468:Alkalies / Q000494:pharmacology; D000693:Anaerobiosis / Q000187:drug effects; D000818:Animals; D018533:Biomass; D001709:Biotechnology / Q000379:methods*; D002417:Cattle; D000431:Ethanol / Q000138:chemical synthesis*; D005947:Glucose / Q000378:metabolism; D006868:Hydrolysis; D008372:Manure / Q000032:analysis; D014866:Waste Products / Q000032:analysis*; D003313:Zea mays / Q000187:drug effects
D000468:Alkalies; D008372:Manure; D014866:Waste Products; D000431:Ethanol; D005947:Glucose