Breeding Of Spinosad High-producing Strain And The Fermentation Process Optimization Research

Spinosad is secondary metabolite produced by Saccharopolyspora spinosa，which is the new-type of the agricultural antibiotic，it can potent insecticidal activity，less toxitity，and low-residue.and they were safty for the useful insects，environmentand human. So it is the most effective agricultural pesticides which uses widely inveterinary and agricultural fields. In this paper，high spinosad-producing mutantsmutated with NTG， Co60and NTG add Co60were screened and its fermentationmedium was optimized. The main results were as follow:1、NTG was used to mutate S. spinosa ASAGF73strain for mutants have beenobtained and showed enhanced spinosad production by25.57%、24.94%、24.42%and23.64%compared to original strain. Co60mutagenesis just got only onemutant， which enhanced spinosad production by20.7%compared to original strain.And the compound mutation， got only three mutants， which enhanced spinosadproduction by30.7%、34.7%and36.4%compared to original strain.2、By means of twice orthogonal experiments we got the optimum formula toenhance the biomass of Saccharopolyspora spinosa was confirm: glucose10g/L、soluble starch20g/L、vegetable oil B10mL/L、vegetable oil E1mL/L、vegetable oilC10mL/L、vegetable oil D15mL/L、vegetable oil A5mL/L， and the biomass in theoptimum formula was increased to30.75%.3、To the fermentation process，we used the feeding method to replenish glucoseand oil， the biomass in the50L fermentation tank was increased by15-20%， andspinosad yield was increased by30%. In the1t fermentation tank， we control the pHat7.2， dissolved oxygen over40%， temperature between28℃to29℃，rotatespeed control at85rpm. In97h the biomass got the top of28.6， in160h the spinosadyield got the top.