Strain Screening Of Hainanmycin Production And Fermentation Process Optimization

Hainanmycin is one of orthosomycin antibiotics with digestion enhancive effect. It characterizes with safety, efficacy and low toxicity and persistence, and is widely used in animal production. To improve the fermentation productivity, the strains were rationally screened and stored, and fermentation processs was optimized with hainanmycin producing species Streptomyoes padunus var. dongfanggeusis.The strains were mutated by microwaves and the mutants were screened on hainanmycin resistant plates combined with the rational screening. Hainanmycin high-yeild strain FCD-19 was obtained. Its productivity reached 4300μg/ml, 50% higher than the original strain. Subculture of four generations indicated that strain FCD-19 were genetically stable. Among three methods for strain preservation by dried sand, under -70℃, and 5℃storage, the most efficient method is stored at -70℃.Carbon and nitrogen sources were firstly screened by the single factor experiments and the composition was further tested through the orthogonal experiments. The final optimal fermentation medium was composed by 1.5%of glucose,8%of soluble starch, 0.05% of MgSO4, 1% of soybean powder, 0.05% of fish protein powder, 0.05% of yeast powder, 0.05% of peptone. The pH was adjusted at 7.0.The effects of seed age and inoculation volume on fermentation process were analyzed. The optimal seed was ready for 44 hours culture, and 8% of seed was inoculated to fermenter. The large scale fermentation was processed at 28℃for 120h by feeding glucose from 48 hours. The ratio of air to fermenter volume was controlled at 0.8. With the optimal medium and fermentation process, the yield of hainanmycin was 4900ug/ml...