抗犊牛腹泻益生菌株BN-9产芽孢条件的优化

Optimization of the Spore Production Conditions of Strain BN-9 as Probiotics to Prevent Calf Diarrhea

解淀粉芽孢杆菌(Bacillus amyloliquefaciens)BN-9菌株是一株能够抑制犊牛腹泻病原菌大肠杆菌(Escherichia coli)的益生菌。为提高该菌株的芽孢生成率,对其产芽孢条件进行了优化。采用单因素试验方法,选择益生菌BN-9菌株的适宜碳源、氮源、无机盐;采用正交设计,结合SPSS软件进行分析,优化出BN-9菌株的最适宜的发酵培养基组成和发酵产芽孢条件。BN-9菌株的芽孢生成率最高时,其相应的培养基组成及发酵条件如下:蔗糖为0.25%,黄豆粕粉为1.5%,MgCl2为0.01%,MnSO4为0.01%,种龄12h,接种量4%,装瓶量100mL·250mL-1,培养基初始pH8.0,摇床转速200r·min-1,37℃发酵培养48h。通过研究,确定了BN-9菌株芽孢生成率最高时的培养基组成和发酵条件;优化后,BN-9菌株的芽孢生成率提高到93.83%,相应的细菌数为2.28×108cfu·mL-1。

us amyloliquefaciens strain BN-9, which could strongly inhibit Escherichia coli, the main pathogens causing calf diarrhea. With single factor testing method, the most suitable carbon source, nitrogen source and inorganic salts to spore production of strain BN-9 were chosen. With range analysis and general linear model analysis using SPSS software to results of orthogonal designs, the most suitable fermentation medium and spore production conditions to spore production of strain BN-9 were determined. The ratio of spore production was 93.83% and the total bacterial were 2.28×10^8cfu·mL^-1 when sucrose content was 0.25%, soybean mill 1.5%, MgCl2 content 0.01%, MnSO4 content 0.01%,medium initial pH 8.0, seed age 12h, inoculation volume 4%, media volume 100mL·250mL^- 1,rotation speed 200r·min^-1,cultivating for 48h at 37℃.