A Simple Technique to Enhance the Productivity of ??-endotoxin in Batch Culture

Abstract

A technique to enhance productivity of Bacillus thuringiensis subsp. kurstaki SN5based on inoculum size and productivity data assessment was established, using mediumcontaining 2% GYS in a 2L bioreactor. Results show that a 10% v/v inoculum gave thehighest productivity of 0.042 mg/ml/h at 12h compared with a 15% and 20% v/v inoculumthat gave 0.022 and 0.013 mg/ml/h at 36h and 48h, respectively. When a 10% v/v inoculumwas employed, spore percentage, at 12h was recorded at 35.9% with the highestconcentration of ??-endotoxin of 0.50 mg/ml. The results showed that inoculum size have asignificant effect on spore percentage, productivity of ??-endotoxin and harvesting time andlends the simple technique to enhance ??-endotoxin productivity. All yield data are thehighest in the culture from a 10% v/v inoculum size.