1. College of Energy Xiamen University Xiamen 361102 P.R. China
2. Department of Biological Systems Engineering University of Wisconsin Madison 53719 USA
3. Fujian Engineering and Research Centre of Clean and High-valued Technologies for Biomass Xiamen 361102 P. R. China
4. Xiamen Key Laboratory of Clean and High-valued Utilization for Biomass Xiamen 361102 P. R. China