Detoxification of Wheat Straw Formic Acid Hydrolysis and Xylitol Production

Abstract

Xylitol can be obtained from hemicelullosic fraction of lignocellulosic materials containing D-xylose. Formic acid hydrolysis is widely used in lignocellulose pretreatment. However, formic acid hydrolysis wheat straw cannot be directly used as fermentation subsequently owing to various fermentation inhibitors, especially the formic acid in reaction system and released during pretreatment. This study describes main hydrolysis components and inhibitors prepared by hydrolysis of wheat straw with formic acid solution, and different detoxification methods ware used to romve the inhibitors. Study found treatment of wheat straw hydrolysate with overliming treatment and D311 ion-exchange resin had a good result on reduction formic acid and other main inhibitors, results showed which can eliminate 94% of residual formic acid and with only 15% reducion of xylose. To verify the effectiveness of different detoxification methods, hydrolysates of detoxification werr fermented by Candida.tropicalis AS2.1776, and the results also found that the hydrolysate treatmented with overliming treatment and D311 ion-exchange resin have the hightest xylitol yield.