| Pleuromutilin is produced by fungi Pleurotus passeckerianus and Pleurotus mutilis. It was Kavanagh, et al. who first isolated and identified this antimicrobial substance, and made it the empirical formula as C22H34O5. F. Knauseder studied the fermentation of pleuromutilin-producing stain in 1976. Pleuromutilin is mainly used for the treatment of gram-positive bacteria, spirochetes and mycoplasma infection. Tiamulin, a derivative of pleuromutilin, was found when people studied the relationship between chemical structure and antibacterial activity of pleuromutilin. The antibacterial activity of Tiamulin is 10-100 times higher than the parent compound. It has been a trend to study the chemical structure and antibacterial of pleuromutilin derivatives for decades, expecting to get antibiotic drugs with high activity and low toxicity.The production and application of pleuromutilin are very restricted due to low antibiotic yield and profit in China. In this study, the growth and fermentation conditions of pleuromutilin-producing strain were investigated to get better results. Mutant strains with high-yield of pleuromutilin were expected by examination of the antibacterial activity of pleuromutilin after electron and heavy ion irradiation.The results of the experiments showed that the optimal medium of pleuromutilin-producing strain was the modified PDA medium(g/L):glucose 20g, peptone 10g, yeast extract 10g, KH2PO42g, MgSO4·7H2O 1g. The optimal pH and fermentation temperature were 6.0 and 28℃, respectively. Mutant strains with high-yield of pleuromutilin were screened out at irradiation doses of 50Gy, 100Gy and 200Gy. These results would provide reference data for the production and application of pleuromutilin-producing strain in the future. Mutants with high-yield of pleuromutilin were selected out after irradiation. It implies that as an effective mutagenic source, radiation has a great potential in the breeding of pleuromutilin-producing strain.
|
PDF Full Text Request