Optimization of the fermentation culture media of Bacillus thringiensis using sewage sludge as raw material
南京城市污泥发酵苏云金杆菌培养基成分优化

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.