青贮用黄曲霉毒素降解菌株的产芽胞条件优化

目的]利用正交试验设计对青贮用黄曲霉毒素降解菌株N-1a产芽胞条件进行优化。方法]以菌株的菌体生物量和芽胞形成率作为考察指标,利用单因素试验和正交试验设计优化菌株N-1a的发酵用培养基组成和培养条件。结果]优化后的N-1a最佳产芽胞培养基组成配比为：玉米粉2.0%,黄豆饼粉1.0%,MnSO4·H2O 0.10%,MgSO4·5H2O 0.01%;最佳产芽胞条件为：p H值为7.0,发酵时间48 h,接种量4%,装液量75 m L/250 m L培养基;在该条件下,N-1a的菌体生物量为6.08×10^8cfu/m L,芽胞形成率为81.25%。结论]菌株N-1a的摇瓶产芽胞条件为其中试生产提供了实验依据。

Optimization of Spore Formation Conditions of an Aflatoxin-degrading Bacillus subtilis Strain Used in Silage Preparation

Objective]To optimize the spore formation conditions of an aflatoxin-degrading Bacillus subtilis strain N-1 a used in silage preparation by employing orthogonal experimental design.Methods]The strain biomass and spore formation rate were used as the assessment index to evaluate the optimized condition combinations. The fermentation medium components and their corresponding ratio as well as the culture conditions were determined and optimized by using single factor experiment and orthogonal experimental design. Results]The optimal ratio of the medium components were as followed： corn meal 2.0%,soybean cake powder 1.0%, MnSO4·H2O 0.10%, MgSO4·5 H2O 0.01%; the optimum spore formation conditions were as followed：p H value 7.0, fermentation duration 48 h, inoculation amount 4%, loading liquid volume 75 m L per 250 m L medium; under these conditions, the biomass of the N-1 a stain was 6.08 ×10^8 cfu/m L and the spore formation rate was 81.25%. Conclusion]The determination of the optimal spore formation conditions of the N-1 a strain in shake flask production provided a theoretical basis for the pilot scale production.