Mutagenetic and Breeding for High Natamycin-producing Strain

Natamycin,as a new kind of polyene macrolide antibiotics,has been widely used in food preservation.The objective of this experiment was to obtain high natamycin-producing variant strains from Streptomyces gilvosporeus ATCC13326 by the methods of UV-induced mutation and streptomycin resistance screening.Streptomycin minimal inhibition concentration of the original activated strain was 8.0 μg/mL.The spore suspension was treated with UV light with the dose of 90% lethal and then inoculated on agar plates containing 8.0 μg/mL streptomycin for screening.Finally,5 mutants were picked out to determine shaking fermentation properties.After 26 hour's seed fermentation and 96 hour's shaking fermentation,extract broth of mutant were detected at 303 nm by ultraviolet spectrophotometer and then the natamycin yields of fermentation were gained.The results showed that the natamycin fermentation yields of original strain and the two mutation strains were 1.229 g/L,1.552 g/L and 1.776 g/L,respectively.The natamycin yields of the two mutation strains were 26.3% and 44.5% higher than that of the original strain.