a new medium for improving spinosad production by saccharopolyspora spinosa

Background: spinosad (a mixture of spinosyns a and d) is a unique natural pesticide produced by saccharopolyspora spinosa. with regard to attempts to improve s. spinosa by classical mutagenesis, we propose that the bottleneck of screening out high spinosad- production strains is probably caused by the fermentation media. objectives: the current study aimed to identify a new medium to extensively investigate the potential of s. spinosa strains to pro- duce spinosad. materials and methods: statistical and regressive modeling methods were used to investigate the effects of the carbon source and to optimize the production media. results: the spinosad production of s. spinosa co121 increased 77.13%, from 310.44 ± 21.84 µg/ml in the initial fermentation medium (with glucose as the main carbon source) to 549.89 ± 38.59 µg/ml in a new optimized fermentation medium (98.0 g of mannitol, 43.0 g of cottonseed flour, 12.9 g of corn steep liquor, 0.5 g of kh2 po4 , and 3.0 g of caco3 in 1 l of h2 o; ph was adjusted to 7.0 before autoclaving). after screening 4,000 strains, an overall 3.33-fold increase was observed in spinosad titers, starting from the parental strain co121 in the original fermentation medium and ending with the mutant strain j78 (1035 ± 34 µg/ml) in the optimized medium. conclusions: the optimized fermentation medium developed in this study can probably be used to improve spinosad production in screening industrial strains of s. spinosa.