초록
<P><B>Abstract</B></P> <P>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 <I>Candida guilliermondii.</I> The xylitol concentration and yield obtained was 28.78 g L<SUP>−1</SUP> and 0.59 g g<SUP>−1</SUP> respectively, in 37 h. The productivity of 0.81 g L<SUP>−1</SUP> h<SUP>−1</SUP>, 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.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Effects of upstream processing on fermentation of hemicellulosic hydrolysate. </LI> <LI> Conversion of hemicellulose to monomeric sugars with low concentration of acid. </LI> <LI> Development of an effective detoxification for adequate removal of inhibitors. </LI> <LI> Highest productivity of xylitol by fermentation using poplar wood hydrolysate. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>