高效降解棉酚菌种的筛选及棉粕发酵脱毒工艺研究

Screening of gossypol-degrading strain and its application in fermentation of cottonseed meal

通过醋酸棉酚YPG培养基多级逐步驯化筛选,结合棉粕固态生物发酵的方法,筛选出1株高效降解棉酚的热带假丝酵母JD-9。通过单因素试验初步确定了棉粕发酵脱毒的工艺条件,进一步利用分式析因试验设计法,对影响棉粕脱毒率的因素进行了筛选,方差分析表明,影响棉粕发酵脱毒的主要因素为热带假丝酵母JD-9接种量和卡氏酵母JD-13接种量。通过响应面分析法和典型性分析得出棉粕发酵脱毒的最优条件为:热带假丝酵母JD-9接种量4.42%,卡氏酵母JD-13接种量0.56%,发酵时间48 h,发酵温度30℃,料水比1∶0.8,棉粕中的棉酚从987.5 mg/kg降解至85.9 mg/kg,脱毒率达到91.3%。

The YPG medium containing acetic gossypol was used for the gossypol - degrading strain screening. A strain of Candida tropicalis JD - 9 with high efficiency of gossypol - degrading was screened out. The methods of single factor experiments, fractional factorial experimental design and central composite experimental design were used to optimize the process parameters for detoxification of gossypol in cottonseed meal by Candida tropicalis JD -9 during solid substrate fermentation. The optimum fermentation conditions were as follows ：inoculums level of JD -9（ Candida tropicalis）4.42%, inoculums level of JD - 13 （S. carlsbergensis）O. 56%, incubation time 48 h, incubation temperature 30 ℃, ratio of material to water 1 ： 0.8. Under the optimum conditions, the content of gossypol reduced from 987.5 mg/kg to 85.9 mg/kg,and the detoxification efficiency was up to 91.3%.