Mutation Breeding, The Production Of Surfactant Oil Production Strains

Biosurfactants synthesized by microorganisms are natural surfaceactive compounds. Like synthetic surfactants, biosurfactants can reduce the surface and interfacial tensions of adueous media. However,they have several out- st a nding advantages over the chemical surfactants, such as lower toxicity; higher biodegradability; better environmental compatibility. So biosurfactants will have a wide-range of applications for various industries such as enhancedoil recovery, remediation of organics and metals, food additives, cosmetic additives,and med- icine and in biological control.In this paper the strains are identified and the character of the strains are studied. By the experimental results of the morphological structure, physiological characteristics and by the comparison of its whole sequence of l6S rDNA with the type strains in Genebank, it was showed that I6S rDNA of the stain HDY and that of Bacillus subtilis was more than 98 percent of homogenous. Therefore bacterium strain SD59 was identified as Bacillus subtilis.Then the high yields lipopeptide–producing mutant strain was obtained from HDY by series of mutagenetic treatment ,as UV, DESand UV&DES.The production of Lipopeptide was 430mg/L.which was 1.27times more then the initial strain HDY.On the fermentation optimization conditions of strain UD-328,the fistPB design was used to determined as sodium nitrate, Glucose andNaCl were the main affecting on lipopeptide produetion.then the optimum fermentation medium was determined according to BB response surface analysis with DE software. After above experiments, the optimized composition of medium(g/L) was obtained: sodium nitrate 21.9, Glucose31.8, Phosphorus source 12,Yeast1.2,CaCl21.0,MgSO4 0.1,FeSO4 1.4,NaCl 3.34. In this medium, lipopeptide production was 1046.12g/L.