Ian Doran1, Geoff Moxley1, Zhigang Zhu1, and Percival Zhang2. (1) Biological Systems Engineering Department, Virginia Tech University, 411 Latham Hall, Blacksburg, VA 24061, (2) Biological Systems Engineering Department, Institute for Critical Technology and Applied Science (ICTAS), Virginia Tech University, 210-A Seitz Hall, Blacksburg, VA 24061
Effective utilization of biomass as a sustainable source of biofuels and value-added biochemicals is severely hindered by the high processing costs and relative low sugar yields. Switchgrass has gained national attention as a potential indigenous biomass source well suited to many regions in the US. The success of industrial process depends on the trade-off art of compromising processing costs, capital investment, and product revenues. A new cellulose-solvent-based lignocellulose fractionation (CSLF) technology has been developed for separating lignocellulose components based on their different solubility in different solvents (Zhang et al. Biotechnol. Bioeng. 2007. 97: 214). We further optimized pretreatment conditions for high sugar release at lower enzyme loading. The optimal pretreatment conditions for switchgrass were determined to be 84% H3PO4 at 50°C for 60 minutes. In order to reduce enzyme use, we further investigated to decrease the enzyme loading from 15 FPU of cellulase per gram of glucan to lower levels without significant reduction in sugar yields in presence of other potential hydrolysis additives such as surfactants. Scanning electron microscopy (SEM) images clearly show that CSLF can completely destruct fibril structure of lignocellulosic biomass.
