南京城市污泥发酵苏云金杆菌培养基成分优化

研究南京江心州污水处理厂污泥作为原料发酵生产苏云金杆菌(Bacillus thringiensis)的可行性,并与常规的工业发酵黄豆粉培养基发酵B.thringiensis做比较,结果表明,以固形物含量3%的污泥为基质发酵B.thringiensis,其菌体数及芽孢数只有108个/mL,而工业发酵黄豆粉培养基发酵B.thringiensis菌体数及芽孢数为109个/mL。优化污泥发酵生产苏云金杆菌培养基成分,将污泥与不同量的黄豆粉复配作基质发酵B.thringiensis,结果发现,在污泥中添加15 g/L黄豆粉可基本满足工业发酵生产的需要,发酵72 h获得的B.thringiensis细胞总数及芽孢数均在109个/mL以上。以黄粉虫作试虫的生物毒性实验表明,复配后的基质与工业发酵黄豆粉培养基生产的B.thringiensis孢晶混合液的毒性相当。

Optimization of the fermentation culture media of Bacillus thringiensis using sewage sludge as raw material

Sewage sludge from Nanjing Jiangxinzhou sewage treatment plant was used as raw material to produce Bacillus thingiensis.Soybean meal medium,a traditional culture medium in B.thringiensis production,was also used as the control in this study.It was found that when sewage sludge was used as an alternate culture medium to produce B.thringiensis,the number of viable cells and spores is only 108cfu/mL,but that of viable cells and spores is 109cfu/mL when B.thringiensis cultured with soybean meal medium.The experiment medium was optimized by using the mixture of sewage sludge with different content soybean meal to produce B.thringiensis.It was found that sewage sludge mixed with 15 g/L soybean meal culture medium could meet industrial production,the number of viable cells and spore is both over 109cfu/mL cultured B.thringiensis in this medium for 72 h.Entomotoxicity was evaluated by Tenebrio molitor with surface contamination method.The insecticidal effect of the sporulation and δ-endotoxin produced from the optimized medium and soybean meal medium were no remarkable difference.