响应面法优化不同型态热带假丝酵母发酵生产木糖醇的工艺

Optimization for xylitol fermentation by different forms of Candida tropicalis with response surface methodology

利用Design Expert软件对菌丝型和酵母型热带假丝酵母发酵生产木糖醇实验进行设计及结果分析,建立木糖和木糖醇浓度与4个关键因子(菌型、发酵温度、pH、初始木糖浓度)的二次多项式回归模型,并对模型进行解析。结果表明:菌丝型热带假丝酵母转化木糖为木糖醇的能力高于酵母型;升高发酵温度,有利于木糖转化为木糖醇,而pH升高对转化过程并没有明显促进;发酵液中初始木糖浓度与木糖转化率呈正相关关系;获得最佳发酵工艺条件为菌种采用菌丝型酵母,发酵温度37℃,pH8,初始木糖浓度60mg/mL,此时木糖醇浓度达到17.21mg/mL。

The xylitol fermentation experiments by using mycelial form and yeast-like form of Candida tropicalis were designed and the results were analyzed.The quadratic polynomial regression model including the concentration of xylose and xylitol,as well as four key factors（forms,fermentation temperature,pH,initial concentration of xylose） were established and analyzed by Design Expert software.The result showed that,the mycelial form had better ability for conversion of xylose to xylitol than yeast-like form;the increase of fermentation temperature was favor to xylose conversion,and a higher pH did not improve the xylose utilization;the initial xylose concentration had a positive correlation with the conversion rate of xylose.The optimal conditions for xylose fermentation were：mycelial type,fermentation temperature 37℃,pH 8.00,initial xylitol concentration 60mg/mL,the concentration of xylitol reached 17.21mg/mL.