Abstract: This work aimed to identify optimum fermentation shaker-flask culture conditions for Bacillus amyloliquefaciens strain 261MY6. Biological characteristics of endophytic bacteria Bacillus amyloliquefaciens 261MY6 from alpine pasture were determined,such as growth temperature,pH value and growth cycle. The fermentation conditions of it was optimized by single factor test and orthogonality. The results showed that strain 261MY6 the highest growth temperature was 56℃,the lowest temperature was 4℃,the lethal temperature was 95℃,and the optimum temperature was 28~36℃. The optimum pH was 5~7. The growth curve of strain 261MY6 showed that it entered the logarithmic growth phase at 5h and entered the stable growth phase at 10h. The optimum ratio of ingredients for the culture medium for 261MY6 was:3 g beef grit,25 g lactose,3 g MgSO₄,7 g yeast extract,1000 mL water,32℃ temperature,14% inoculum volume,40 mL·(150 mL)^-1 liquid volume,210 rpm shaker speed,pH 7.Under these condition,when fermentation time was 30 h in the fermentation tank,the viable count of Bacillus amyloliquefaciens strain 261MY6 reached 2.37×10¹² CFU·mL^-1. Those results laid a foundation for the development of the anti-formulation agent of strain 261MY6.

Key words: Bacillus amyloliquefaciens, Biological characteristics, fermentation process, optimization

摘要： 为提高生防菌株解淀粉芽胞杆菌（Bacillus amyloliquefaciens）261MY6的生物量，本试验对高寒草地内生细菌解淀粉芽胞杆菌261MY6生长温度、pH和生长周期等进行测定，并结合单因素试验和正交设计试验对其发酵培养基和发酵条件进行优化。结果表明，菌株261MY6最高生长温度为56℃、最低温度为4℃、致死温度为95℃和最适温度为28~36℃，最适pH值为5~7，在5 h进入对数生长期，在10 h时进入稳定生长期。最优发酵培养基为：牛肉膏3 g，乳糖25 g，MgSO₄ 3 g，酵母膏7 g，水1000 mL。最优发酵条件为：温度32℃，接种量14%，装液量40 mL·（150 mL）^-1，摇床转速210 rpm，pH 7。最优条件下，发酵261MY6，最佳放罐时间为30 h，活菌数达2.37×10¹² CFU·mL^-1。该结果为菌株261MY6开发为微生物菌剂奠定了基础。

关键词: 解淀粉芽胞杆菌, 生物学特性, 发酵条件, 优化