复合芽胞杆菌共培养条件的响应面优化研究

Optimization of Co-culture Conditions for Compound Bacillus by Response Surface Methodology

在前期筛选出了具有耐盐、促生能力的短小芽胞杆菌(Bacillus pumilus)SC-12和具有高效广谱抗病能力的解淀粉芽胞杆菌(Bacillus amyloliquefaciens)BZ6-1,而且两株菌不存在拮抗作用。为了获得活菌数高、经济效益好的复合芽胞杆菌菌剂,以上述两株菌为研究对象,以活菌数为指标,采用单因素法、最陡爬坡法和Box-Behnken响应面法设计并优化共培养条件,并在100 L发酵罐中进行了验证试验。获得的最佳共培养条件如下:SC-12与BZ6-1的菌落数比例为2∶1(v/v);培养温度为30℃;培养时间为16 h;接种量为3%(v/v);转速为132 r/min;pH值为7.6。以优化后的培养条件进行两个菌株的共培养,得到的菌落数为11.00×10^(8) cfu/mL,比原始发酵得到的菌落数增加了39.20%;在100 L发酵罐中发酵的菌落数达到10.30×10^(8) cfu/mL,比原始发酵的菌落数增加了43.00%。

At the early stage,Bacillus pumilus SC-12 with salt tolerance and growth promotion ability and Bacillus amyloliquefaciens BZ6-1 with high efficiency and broad-spectrum disease resistance were screened,and the two strains had no antagonistic effect.To obtain a compound Bacillus agent with high number of viable bacteria and good economic benefit,the two strains were taken as the research object,and the number of living bacteria was used as the index.The co-culture conditions were designed and optimized by single factor method,steepest climbing method and box Behnken response surface method.The optimum co-culture conditions were as follows:colony number of SC-12 and BZ6-12∶1(v/v),culture temperature 30℃,culture time 16 h,Bacterial inoculation 3%(v/v),rotating speed 132 r/min,pH 7.6.Under the optimized culture conditions,the number of colonies was 11×10^(8) cfu/mL,which was 39.2%higher than the original fermentation colony.The number of colonies in 100 L fermenter reached 10.3×10^(8 )cfu/mL,which was 43%higher than the original fermentation colony.