Sunday, May 3, 2009
3-18
Optimization of rice straw pretreatment by hydrothermal process
An-Yi Wu, Wen-Hua Chen, and Wen-Song Hwang. Cellulosic Ethanol Program, Institute of Nuclear Energy Research, No. 1000, Wenhua Road, Jiaan Village, Longtan, Taiwan
Hydrothermal treatment is an environment-friendly pretreatment process and its effects on lignocellulose biomass are hemicellulose hydrolysis, lignin degradation, cellulose alteration and recovery of polysaccharides. The goal of this study was to define the optimal conditions for hydrothermal treatment of rice straw to provide maximum total sugar yields. In this report, dried rice straw was fractionated by hydrothermal pretreatment, which was carried out at 10% solid loading in the range of 170-220oC for 0-120min. Results show that the solublization of raw material components such as hemicellulose and lignin leads to increase cellulose content in the solid fraction with values between 51%-65%. In comparison to untreated substrate (42.8% dwb), this is an important advantage for the following step of enzymatic hydrolysis. The enzymatic hydrolysis yield increased with pretreatment time and temperature, but xylose degradation in in low xylose recovery became significant. The highest enzymatic hydrolysis yield (91.6%) was obtained at 180oC for 30 min.Furthermore, the optimized conditions were obtained at 200oC for 2 min giving maximum total recovery of 63.6%.