Abstract:

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 has a 96% rate of sporulation. It lays the foundation for the application of Bacillus subtilis XK-1 as a kind of microbial fertilizer.