Sunday, May 3, 2009
3-111
Investigation on effect and mechanism of different surfactant applied in pretreatment of wheat straw
Zhimin Li, Tianxi Zhang, Shi-shen Liao, Xiaochen Yu, Manuel Garcia-Perez, and Shulin Chen. Department of Biological System Engineering, Washington State University, L. J. Smith 213, Pullman, WA 99164
Surfactants including Tween, Polyethylene glycol (PEG ), Pluronic, Span, Cetyltrimethylammonium bromide (CTAB) and biosurfactant have been applied into enzymatic hydrolysis of lignocellulosic materials, which not only improve hydrolytic efficiency but also lower enzyme loading amount. The major mechanisms being suggested for the enhancement of hydrolytic process are that surfactant can reduce the non-productive adsorption of cellulytic enzymes on lignin and act as enzyme stabilizer and effectors. However, there is little work being done on surfactant’s application on pretreatment, in which surfactants may make contribution to improve efficiency of pretreatment and the economics of the entire process. In this study, we hypothesized that surfactant applied simultaneously in the alkaline pretreatment could enhance extracting the hydrolysate of lignin part into another phase and thus improve the efficiency of pretreatment. Results had shown that the effectiveness of surfactants added during pretreatment on the performance of enzymatic hydrolysis depend on pretreatment process, surfactant type and concentration. In the ammonia pretreatment, PEG addition gave rise to the best hydrolytic performance compared with the results with Tween or Pluronic addition, while in the lime pretreatment Pluronic addition improved more sugar release and higher conversion rate compared with other surfactant addition. After the optimization of processes by Response surface methodology (RSM), the performance of hydrolysis and fermentation and the respective mechanism under this condition were investigated and explained via SEM , pyrolysis GC-MS and FTIR experiments.