Development and evaluation of poplar hemicellulose prehydrolysate upstream processes for the enhanced fermentative production of xylitol

摘要

A major bottleneck to the utilization of hemicellulose streams obtained on pretreatment of lignocellulosic residues is the toxins formed during the hydrolysis of the pentose polymers. Low acid (1.75% (w/w) and 120 °C) hydrolysis yielded a 3-fold increase in xylose concentration with low byproduct formation. Efficient detoxification method using vacuum evaporation and solvent extraction techniques removed the major inhibitors, acetic acid (80%) and furfural (98%) with little loss of sugars. The effectiveness of hydrolysis and subsequent detoxification was ascertained by the fermentation of detoxified hydrolysate with Candida guilliermondii. The xylitol concentration and yield obtained was 28.78 g L~(−1) and 0.59 g g~(−1) respectively, in 37 h. The productivity of 0.81 g L~(−1) h~(−1), the highest reported from wood prehydrolysates, demonstrates that the upstream processing methods are effective. Wood prehydrolysates treated in this way could be used to produce fermentative products like xylitol and other value added products economically and beneficially.