Rational Selection Of High Producting Strain Of Enramycin And The Optimization Of Its Fermention Processes

Enramycin is a kind of peptide antibiotics,widely used as feed additive,has a promoting effect on animal growth.Enduracidin fermentation level of Topfond Pharmaceutical Co.,Ltd.was low.Aiming at the problem,the research of rational selection of high producting strain of enduracidin and the optimization of its fermentative processes was leaded.Achieved the following main research results:1.The mutant strain was screened by the addition of nitrosoguanidine and UV,and the mutant strain was screened on the plate containing four different gradients of enamycin resistance.The results showed that there were 9 strains of mutant strains.After a number of genetic stability tests,one strain ERS42-1,which was the highest strain of enamycin,was picked up to 8400 ± 86 u / mL,13.5% higher than the original strain.2.The fermentation conditions and the fermentation medium components of the mutant strain ERS42-1 were optimized by single factor experiment.The effects of age,inoculation amount,liquid loading,initial pH value of fermentation broth,fermentation culture temperature and culture time on the production of enamycin were investigated.The optimal conditions were as follows: age,48 h;Inoculation amount,10%;loading volume,40 mL /500mL;initial pH value,7.0;fermentation temperature,30 ?;culture time,10 d.And the optimal level of eight factors in the initial fermentation medium of enamycin shake flask was evaluated by Plackett-Burman experiment.The results showed that the yield of rapeseed meal,gluten powder and potassium dihydrogen phosphate significant impact,the highest fermentation area was determined by the central combination test and the response surface method.The optimum fermentation medium was as follows: corn meal 175g/L,corn steep liquor 1g/L,maltodextrin 70g/L,cottonseed cake powder 8.9g/L,gluten flour 55g/L,potassium dihydrogen phosphate 0.06g/L,ammonium sulfate 5g/L,soybean oil 20g/L.Using the optimized shake flask fermentation process,the titer ERS42-1 fermentation flask was increased to 12066 ± 106u/mL,which was 45.4% higher than that of the original fermentation process.3.The test of ERS42-1 production capacity of mutant strain was lenaded in 200 L fermentor.The results showed that the enamycin yield of the mutant strain ERS42-1 was up to12000 ± 96 u / mL,which was 62.2% higher than that of the original strain.