Abstract：Abstract: B. thuringiensis subsp.chinensis strain CT-43 highly produces thuringiensin (Thu). Meanwhile, other metabolizing product (ZZ) was synthesized, but was difficultly removed from Thu. In this study, various media were screened and the G medium was found to inhibite the ZZ synthesis. Based on the G medium, feed-batch fermentation and orthogonal arrays was combined to further inhibit ZZ synthesis and increase the yield of Thu.. The optimal fermentation process was that, After strain CT-43 was cultured in G medium for 20h, patching with 2.0 g/L sodium citrate and 16 g/L glucose and culturing for additional 32h, the peak area ratio of Thu could get 74.84 in the primary extract, which was 2.5 times for 29.85% of LB fermentation. These onditions could create a favorable fermention process to produce more pure Thu and it will enefit for further research. Lastly, HPLC-MS was used to verify the produced Thu. Thu became he major element during the feed-batch fermentation. No ZZ was detected and Thu was not modified after above fermentation process.
