Enzymatic Hydrolysis and Ethanol Fermentation of HighDry Matter Wet-Exploded Wheat Straw at LowEnzyme Loading

摘要

Wheat straw was pretreated by wet explosion using three different oxidizingagents (H202, 02, and air). The effect of the pretreatment was evaluated based on glucoseand xylose liberated during enzymatic hydrolysis. The results showed that pretreatmentwith the use of 02 as oxidizing agent was the most efficient in enhancing overallconvertibility of the raw material to sugars and minimizing generation of furfural as a by-product. For scale-up of the process, high dry matter (DM) concentrations of 15-20% willbe necessary. However, high DM hydrolysis and fermentation are limited by high viscosityof the material, higher inhibition of the enzymes, and fermenting microorganism. The wet-explosion pretreatment method enabled relatively high yields from both enzymatichydrolysis and simultaneous saccharification and fermentation (SSF) to be obtained whenperformed on unwashed slurry with 14% DM and a low enzyme loading of 10 FPU/gcellulose in an industrial acceptable time frame of 96 h. Cellulose and hemicelluloseconversion from enzymatic hydrolysis were 70 and 68%, respectively, and an overallethanol yield from SSF was 68%.