COMPARISON OF ERME GENE EXPRESSION IN SACCHAROPOLYSPORA ERYTHRAEA WILD TYPE AND OVERPRODUCTION MUTANTS

Background and Aim:Erythromycin is the most potent and clinically important member in macrolide antibiotic produced by Saccharopolyspora erythraea. It is a potent 14-membered antibiotic active against pathogenic Gram-positive bacteria. Resistance methylase gene, ermE confers resistance to MLS antibiotics by N6-dimethylation of 23s rRNA at a single site. Ethyl methanesulfonate (EMS) mutagenesis and selection of overproduction mutant, is the most important and convenient method in enhancement of antibiotic production.Methods:In the present study, Saccharopolyspora erythraea was mutagenized using EMS and selection by tylosin resistance mutant to improve yield of erythromycin. In other sides, ermE expression analyzed by Real Time PCR in high producer mutant and wild strains.Results:When EMS used at 4% (w/v) concentration, high producer mutant isolated after 30 minutes of exposure to the mutagen. In total, from 120 colonies of high producer mutant in primary screening, 25 colonies in fermentation environments also showed an overproduction. The expression of ermE gene in five mutant strains from 25 strains that enhanced more than the wild strain. Finally, the RHEMS438 mutant with an average of 2.18 mg / ml antibiotic selected with an increase of production about 3 times that of the wild strain.Conclusion:It was concluded that the expression of ermE gene in high producer mutant increased compared with the wild strain and the ermE expression rate was about 6 times greater than that of the wild strain.

کلیدواژه ها:

Saccharopolyspora erythraea ، Erythromycin ، ermE expression