초록
<P><B>Abstract</B></P><P><B>BACKGROUND:</B> Xylitol, a sugar alcohol widely used in food and pharmaceutical industries, can be produced through biological reduction of xylose present in hemicellulose hydrolysates by <I>Candida tropicalis</I>. However, the aeration rate and by‐products originating from hemicellulose hydrolysis strongly inhibit the production of xylitol in a fermentation process. A two‐stage fed‐batch fermentation system was developed to reduce these inhibitory effects and to improve xylitol production from corn cob hemicellulose hydrolysates by <I>C. tropicalis</I>.</P><P><B>RESULTS:</B> Results of batch fermentations indicated that high xylitol production could be obtained from <I>C. tropicalis</I> at an initial xylose concentration of 80 g L<SUP>−1</SUP> in corn cob hydrolysate medium at an aeration rate of 0.4 vvm at the micro‐aeration stage. In the two‐stage fed‐batch fermentation process, 96.5 g L<SUP>−1</SUP> xylitol was obtained after 120 h, giving a yield of 0.83 g g<SUP>−1</SUP> and a productivity of 1.01 g L<SUP>−1</SUP> h<SUP>−1</SUP>, which were 12.16% and 65.57% higher than those in a batch fermentation.</P><P><B>CONCLUSION:</B> High xylitol production can be achieved in a two‐stage fed‐batch fermentation process, in which the negative effects of aeration rate and inhibitory compounds on xylitol formation can be considerably reduced. Copyright © 2011 Society of Chemical Industry</P>