| Bacillus pumilus HR10 is an excellent strain with growth-promotion and anti-adversity effect. Exploring the optimal fermentation and culturing conditions for sporulation of HR10 strain has an important guiding significance for the production and fermentation on a larger scale. The number of bacterial cells and gemmae were counted by diluted spreading plate method and calculated the gemma rate. Carbon source, nitrogen source and inorganic salt for HR10 strain sporulation medium were analyzed by single factor and orthogonal test, and the single-factor optimization of several fermentation factors affecting HR10 strain sporulation was carried out by shake flask fermentation. The results showed that the best components of the sporulation medium of strain HR10 were: glucose 1%, molasses 1%, soybean cake powder 2%, KCl 0.3%, MnSO4 0.4%. The optimal fermentation conditions were: 37 ℃, pH 7, 250 mL flask filled 50% volume with liquid, inoculation volume 5%, rotation speed 220 r/min, cultured for 52 h. The number of gemmae can reach 2.37×1010 cfu/mL, and the gemma rate can reach 94.46%. As compared with initial medium, the number of gemmae increased by 60.77 times, and laid a foundation for its industrialized production. |
