Soaking pretreatment of corn stover for bioethanol production followed by anaerobic digestion process.
The production of ethanol and methane from corn stover (CS) was investigated in a biorefinery process. Initially, a novel soaking pretreatment (NaOH and aqueous-ammonia) for CS was developed to remove lignin, swell the biomass, and improve enzymatic digestibility. Based on the sugar yield during enzymatic hydrolysis, the optimal pretreatment conditions were 1 % NaOH+8 % NH(4)OH, 50°C, 48 h, with a solid-to-liquid ratio 1:10. The results demonstrated that soaking pretreatment removed 63.6 % lignin while reserving most of the carbohydrates. After enzymatic hydrolysis, the yields of glucose and xylose were 78.5 % and 69.3 %, respectively. The simultaneous saccharification and fermentation of pretreated CS using Pichia stipitis resulted in an ethanol concentration of 36.1 g/L, corresponding only to 63.3 % of the theoretical maximum. In order to simplify the process and reduce the capital cost, the liquid fraction of the pretreatment was used to re-soak new CS. For methane production, the re-soaked CS and the residues of SSF were anaerobically digested for 120 days. Fifteen grams CS were converted to 1.9 g of ethanol and 1337.3 mL of methane in the entire process.
College of Life Science, Capital Normal University, No.105, Northwest Third Ring Road, Beijing 100048, China.
Zhuang
Z
Zuo
Shen
S
Tian
Zebing
Z
Chen
Jia
J
Li
Xiushan
X
Yang
D000468:Alkalies / Q000494:pharmacology; D000693:Anaerobiosis; D056804:Biofuels / Q000032:analysis*; D001709:Biotechnology / Q000379:methods*; D050260:Carbohydrate Metabolism; D000431:Ethanol / Q000138:chemical synthesis*; D005285:Fermentation; D006868:Hydrolysis; D008031:Lignin / Q000378:metabolism; D008697:Methane / Q000032:analysis; D013816:Thermodynamics; D013997:Time Factors; D014866:Waste Products / Q000032:analysis*; D003313:Zea mays / Q000737:chemistry*
D000468:Alkalies; D056804:Biofuels; D014866:Waste Products; C036909:lignocellulose; D000431:Ethanol; D008031:Lignin; D008697:Methane