초록
<P><B>Abstract</B></P> <P>It is a great challenge to efficiently utilize xylose in fermentation with high solid loadings for the economically feasible production of lignocellulosic ethanol. However, 20% solid loading of dry dilute acid pretreated corn stover (DDAPCS) decreased 66.3% of the xylose consumption compared to yeast extract peptone dextrose and xylose (YPDX) medium, which was significantly larger than 16% solid loading (9.4%). To overcome those problems, several two-step processes for simultaneous saccharification and co-fermentation (SSCF) were developed by inoculating a water extract of 16% solid loading DDAPCS with microorganisms in the first fermentation step. During the first step, the relatively lower inhibitor concentrations (compared to 20% solid loading), decreased glucose concentration, and the absence of enzymatic hydrolysis residues (EHR) were beneficial for the use of xylose and enabled up to 75.6% of the xylose to be converted to ethanol. With an optimized fed-batch strategy of two-step process, the residual xylose concentration reduced by 55.6% with 20% solid loading, and the maximum ethanol concentration and yield increased by 30% and 16.6%, respectively.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The effect of water extract, enzymatic hydrolysate and EHR was studied. </LI> <LI> Water extract and EHR of DDAP repressed the performance of yeasts. </LI> <LI> Two-step SSCF process effectively improved the xylose consumption and ethanol yield. </LI> <LI> Inhibitors tolerance and xylose utilization ability were enhanced after first step. </LI> </UL> </P>