枯草芽孢杆菌XK-1产芽孢条件的优化

Optimization of Medium Composition for the Production of Bacillus subtilis XK-1 Spores

为在最大程度上提高有机磷降解菌——枯草芽孢杆菌XK-1的芽孢产量,对其产芽孢的条件进行系统研究。以菌体芽孢化的方式增强该菌适应性,采用单因素和正交试验的方法,考察不同的氮源、碳源、无机盐、pH、温度、培养时间、接种量对枯草芽孢杆菌形成芽孢的影响。结果表明:XK-1产芽孢的最佳培养基组成为:3%麸皮,3%大豆蛋白胨,0.1%CaCl2,0.05%NaCl,在此基础上的最佳培养条件为pH7.5,温度为40℃,发酵时间为48h,接种量为2%。经优化后,该菌株的产芽孢率达96%,为下一步该菌株在复合生物肥中的应用打下基础。

Strain Bacillus subtilis XK-1 played a major role in biofertilizer research, but it was easily influenced by hypertonic and halophilic environment. So this study was to improve Strain Bacillus subtilis XK-1 compatibility by using Strain Bacillus subtilis XK-1 spore. In order to improve the formation rate and the quantity of the spore, systematic research was taken under cultural conditions. The medium composition for the production of Bacillus subtilis XK-1 spores was optimized by using the single factor and orthogonal tests. Various factors, such as carbon sources, nitrogen sources, inorganic salts, initial pH, temperature, fermentation time and inoculum size were investigated. The results showed that the optimum medium was as follows： bran 3%, bean peptone 3%, CaCl2 0.1%, NaCl 0.05%. The optimum culture conditions were as follows： pH 7.5, temperature 40℃, inoculum volume 20 mL/L and fermentation time 48 h. On the optimized condition, Bacillus subtilis XK-1 had a 96% rate of sporulation. It laid the foundation for the application of Bacillus subtilis XK-1as a kind of microbial fertilizer.