枯草芽孢杆菌DZ1的培养基及发酵条件优化研究

Optimization of Fermentation Conditions and Media of Bacillus subtilis DZ1

本研究以枯草芽孢杆菌(Bacillus subtilis)DZ1作为研究试材,通过单因子试验及正交试验,确定其适宜的摇瓶培养基及发酵条件。结果表明,培养时间、培养基及培养条件对Bacillus subtilis DZ1的活菌数影响差异显著。DZ1的最佳种龄为12 h,最佳碳源和氮源分别是可溶性淀粉和酵母膏。影响枯草芽孢杆菌DZ1活菌数的主要因素为酵母膏,其次为可溶性淀粉,K2HPO4和MgSO4.7H2O影响较小。DZ1的最优培养基组合为可溶性淀粉1%,酵母膏1%,K2HPO4 0.15%,MgSO4.7H2O 0.02%,CaCl2 0.01%,在此条件下,其活菌数可达44.1×10 8 CFU/mL。单因子试验结果表明,DZ1的适宜摇瓶培养条件分别为培养基温度34℃,初始pH值7.0,摇床转速180 r/min和接种量7%。

The flask-shaking fermentation conditions and media of Bacillus subtilis DZ1 was studied through the single factor experiments and orthogonal experiments. The results showed that the culture time, fermentation conditions and media had significant effects on the survival of Bacillus subtilis DZ1. The optimal seed age was 12 hours after Bacillus subtilis inoculation, and the best carbon sources and nitrogen sources were soluble starch and yeast extract, respectively. Yeast extract was the most important factor affecting Bacillus subtilis populations, and what was followed was soluble starch. However, K2HPO4 and MgSO4＂7H20 had little effects on its populations. The optimum culture media for the strain Bacillus subtilis DZ1 were determined as the mixture of 1% soluble starch, 1% yeast extract, 0.15% KEHPO4, 0.02% MgSO4＂7H20, and 0.01% CaC12. Under this optimized conditions, the maximum amount of Bacillus subtilis DZ1 reached 44.1 x 108 CFU/mL. The single factor experiment results showed that the fermentation conditions were identified as the culture temperature of the shaking table 34℃, the initial pH of the medium 7.0, the rotation speed 180 r/min, as well as the inoculation amount 7%.