假丝酵母发酵玉米芯半纤维素水解液生产木糖醇

玉米芯是廉价的可再生资源，利用玉米芯半纤维素水解液发酵生产木糖醇，具有工艺简单、能耗小、产品质量好等特点。假丝酵母（Candida tropicalis）菌株经驯化后显著地提高了对水解液中发酵抑制物的耐受力，从而提高了木糖醇得率。确定发酵温度、初糖浓度、pH值、接种量、通气量等因素对发酵生产木糖醇的影响，并对其进行优化，优化结果为接种量10％（v／v），种子龄24h，温度为30％，起始pH值为5．5，并且在发酵过程中补加适量氮源，木糖醇得率达61％。该方法大大降低了预处理的成本，有良好的应用前景。

Xylitol production from corn cob hydrolysate by Candida tropicalis

Corncob is a kind of cheap renewable lignocellulosic resource. The bioconversion of hemicellulosic hydrolysate to xylitol by Candida tropicalis features simple process, low energy consumption and good quality of products.Candida.tropicalis was more tolerant to fermention inhibitor after domestication, thus the yield of xylitol increased.In this paper, the effects of fermented temperature, initial sugar concentrate, pH value, inoculum and ventilation on xylitol production were determined, and then these factors were optimized by orthogonal experiment.The optimum fermentation conditions were as follows: inoculums rate 10% (volume ratio), culture time 24 h, temperature 30℃, initial pH value 5.5, and adding appropriate amount of nitrogen source.The yield of xylitol has increased by 61% on this condition.This process can effectively reduce the pretreatment costs, with broad prospects of applications.