To make biomass more accessible for enzymatic hydrolysis, lime pretreatment of Miscanthus giganteus with oxidants was explored from 100 to 150 °C. Composition data for the recovered solid were obtained to determine the effects of the reaction time, lime dosage, oxidant loading, and temperature on sugar production efficiency. Under selected conditions (0.2 g of lime/g of biomass, 200 psig O2, and 150 °C for 1 h), delignification was 64.7%. The pretreated biomass was then followed by enzymatic hydrolysis. The yield of cellulose in the recovered solid to glucose was 91.7% and hemicellulose to xylose was 67.3%, 7.1 and 18.2 times larger than those obtained from raw biomass, respectively. Pretreatment with oxidants substantially raised delignification of raw M. giganteus, thereby enhancing enzymatic hydrolysis to sugars, while results were not improved when pretreatment included ammonium molybdate.
The authors are grateful to the Energy Biosciences Institute, University of California, Berkeley, Berkeley, CA, for financial support, Dr. Stefan R. Bauer, Valerie D. Mitchell, and Ana Belen Ibanez Zamora for technical assistance, and Jason Cai for fruitful discussions. The authors thank the China Scholarship Council for financial assistance to Fuxin Yang during his stay at University of California, Berkeley.