초록
<P><B>Graphical abstract</B></P><P>2,3-Butanediol production in bioreactor by <I>Klebsiella oxytoca</I> fermentation using hydrolysate solution from the second-step hydrolysis of <I>Jatropha</I> hulls.<ce:figure id='f0035'></ce:figure></P><P><B>Highlights</B></P><P>► Neutral detergent removed the extractives of <I>Jatropha</I> hulls to avoid inhibitors. ► A two-step process hydrolyzed <I>Jatropha</I> hulls with hydrolysis yield 64%. ► Yields of diol were 35.6% and 41.4% in flasks from the two-step hydrolysates. ► Fermentation time was reduced from 60 in flasks to 40h in a controlled bioreactor. ► Glucose from the second-step hydrolysis was more suitable for fermentation.</P> <P><B>Abstract</B></P><P><I>Jatropha</I> hulls were successfully for the first time used as raw materials for the production of 2,3-butanediol via dilute sulfuric acid hydrolysis and fermentation with <I>Klebsiella oxytoca</I>. Two-step hydrolysis was used to effectively hydrolyze the hulls at 150°C after pretreatment. In the first-step, hemicellulose was hydrolyzed under mild conditions (0.5h, 1.5% acid) to avoid secondary decomposition. The remained cellulose was further hydrolyzed in the second-step under severer conditions (1h, 4% acid). After hydrolysis, total hydrolysis yield was 64%, which was much higher than that (37%) from the first-step. Maximum yields of 2,3-butanediol and acetoin in flask experiments were 35.6% and 41.4% from the hydrolysates of the first- and second-step hydrolysis, equivalent to 71.2% and 82.8% of the theoretical values, respectively. Similar yields were obtained in a controlled bioreactor but with higher productivities. <I>Jatropha</I> hulls are attractive raw materials for the production of 2,3-butanediol with high yield.</P>