Abstract:The fermentation yield of spinosad, a biological pesticide, limits its industrialization development. To enhance spinosad production, Saccharopolyspora spinose T1 was mutagenized using atmospheric and room temperature plasma (ARTP) and diethyl sulfate (DES). The high-yield strain, S. spinosa F5, was obtained by streptomycin and rhamnose as screening factors combined with microplate culture. After fermentation, the yield of spinosad was 572.3 mg/L, an increase of 35.9% compared to that of the parent strain. Through single factor experiment and response surface test, the optimum addition amounts of sodium citrate and isoleucine were determined to be 0.46 g/L and 0.10 g/L, while the optimum addition volume fraction of soybean oil was 1.77%. Under this condition, the spinosad production reached 707.2 mg/L, and batch fermentation in a 5 L fermenter showed a yield close to 800 mg/L after 240 h fermentation. Further batch-fed fermentation resulted in a production of 1 175.5 mg/L after 264 h fermentation. The results showed that the compound mutation combining ARTP and DES breeding, along with the addition of exogenous inducers, could significantly increase the yield of spinosad.
