Xylitol bioproduction from wheat straw: hemicellulose hydrolysis and hydrolyzate fermentation

Abstract

AbstractA 22 central composite design with five center points was performed to estimate the effects of temperature (120, 130 and 140 °C) and acid loading (100, 150 and 200 mg g−1) on the yield of monomeric xylose recovery from wheat straw hemicellulose (YS/RM). Under the best hydrolysis condition (140 °C and 200 mg g−1), a YS/RM of 0.26 g g−1 was achieved. After vacuum concentration and detoxification by pH alteration and active charcoal adsorption, the hydrolyzate was used as source of xylose for xylitol bioproduction in a stirred tank reactor. A xylitol production of 30.8 g L−1 was achieved after 54 h−1 of fermentation, resulting in a productivity (QP) of 0.57 g L−1 h−1 and bioconversion yield (YP/S) of 0.88 g g−1. The maximum specific rates of xylose consumption and xylitol production were 0.19 and 0.15 g g−1 h−1, respectively. Copyright © 2006 Society of Chemical Industry