Abstract：Spinosad, produced by Saccharopolyspora spinosa, is a kind of high-efficiency and low-toxicity bio-insecticide wildly used as pesticide, veterinary drug, hygienic insecticide, etc. The ability of S. spinosa to utilize starch and maltose was low, making a huge obstacle for the industrial fermentation of spinosad. In order to improve the ability of S. spinosa to use starch, the maltose transport related genes malEFG from Streptomyces avermitilis were expressed in a spinosad high-yield strain S. spinosa ASAGF73. The integration expression vector pSET152::malEFG was transformed into ASAGF73 through conjugal transfer, and the malEFG genes were successfully expressed in the resulting transformant. ASAGF73 and the transformant were cultured in single carbon source medium to study the effects of malEFG, showing that the transformant consumed dextrin and maltose betterly than ASAGF73. In the media with dextrin or maltose as the sole carbon source, expression of malEFG genes promoted obviously the growth of S. spinosa, resulting in improvement of spinosad yields. This study provides theoretical significance and application value for spinosad fermentation process using starch as main carbon source.
