Insecticide Spinosad Strain Selection And Fermentation Process Optimization

Spinosad is derived from the fermentation of a naturally occurring actinomycetes bacterium, Saccharopolyspora spinosad. It is a novel microbial broad-spectrum insecticide, composed of a mixture of two most active naturally occurring metabolites (spinosyns A and D). The attributes of spinosad including unique chemistry and mode of action, high levels of activity against economically important pests, a short half-life, degradation to natural building blocks, and large margins of safety for mammals, birds, fish and even most beneficial insects. In this dissertation, strain improvement, optimization of spinosad fermentation process and scale-up of fermentation processes were investigated.Strain improvement was performed by mutation and rational screening to obtain a higher spinosyns-producing strain. After UV, microwave, space condition mutation, the higher productive strain S.spinosa J-SM-523 was selected. The productivity reached 354μg/ml, which was 177.0% more than that of the parent strain.The optimization of the seed medium was studied. A new seed medium made the strain grow better was obtained.The optimization of the fermentation medium was studied. Materials can be obtained easily and cost lower. The productivity optimal fermentation medium reached 463 μg/ml, which was 42.5% more than that of the original fermentation medium.Based on the above experimental data, tests in 5 L fermentor were also carried out and a productivity of 263 μg/ml was obtained, which lower than that in the shaking flasks.