초록
<P><B>Abstract</B></P> <P>This study evaluated the possibility of using rapeseed straw hemicellulosic hydrolysate as a fermentation medium for xylitol production. Two yeast strains, namely <I>Debaryomyces hansenii</I> and <I>Candida guilliermondii,</I> were used for this bioconversion process and their performance to convert xylose into xylitol was compared. Additionally, different strategies were evaluated for the hydrolysate detoxification before its use as a fermentation medium. Assays in semi-defined media were also performed to verify the influence of hexose sugars on xylose metabolism by the yeasts. <I>C. guilliermondii</I> exhibited higher tolerance to toxic compounds than <I>D. hansenii</I>. Not only the toxic compounds present in the hydrolysate affected the yeast’s performance, but glucose also had a negative impact on their performance. It was not necessary to completely eliminate the toxic compounds to obtain an efficient conversion of xylose into xylitol, mainly by <I>C. guilliermondii</I> (Y<SUB>P/S</SUB> =0.55g/g and 0.45g/g for <I>C. guilliermondii</I> and <I>D. hansenii</I>, respectively).</P> <P><B>Highlights</B></P> <P> <UL> <LI> Rapeseed straw hemicellulosic hydrolysate was used for xylitol production. </LI> <LI> Different strategies were evaluated for the hydrolysate detoxification. </LI> <LI> <I>C. guilliermondii</I> exhibited higher tolerance to the toxic compounds than <I>D. hansenii.</I> </LI> <LI> Toxic compounds and glucose concentration affected the yeast’s performance. </LI> <LI> Partial removal of toxic compounds was enough to achieve an efficient bioconversion. </LI> </UL> </P>