Optimum Fermentation Medium for Insecticidal Active Substances from Strain TLB15

The optimum fermentation culture medium of strain TLB15 was modified through an orthogonal experiment L18 (37) .The results showed that the optimum fermentation culture medium contained 3.0% corm meal, 2.0% soybean powder, 1.0% sugar, 0.1% ammonium sulfate, 0.3% potassium hydrogen phosphate trihydrate, 0.2% potassium dihydrogen phosphate, and 0.04% magnesium sulfate heptahydrate.The number of viable cells was 4.52×109 cfu·mL-1and the rate of spore formation was 90%after 48hs′fermentation.The 72-h adjusted mortality of TLB15 strain fermentation liquid on the larvae of Plutella xylostella and Spodoptera exigua were 66.93%and 69.07%, respectively.