Natal Streptomyces (streptomyces Natalensis) Production Satisfied The Selection Of The Producing Strain Of Natamycin

26-membered ring polyene macrolide antibiotics Natamycin can effectively inhibit yeast and mold growth,which serves as a broad-spectrum antifungal agent which is effective in the therapy of medical treatment and protection of foods, and it is mainly produced by Streptomyces natalensis, Streptomyces chattanovgensis and Streptomyces gilvosporeus. In order to increase the yields of Natamycin, the cultural mode of Natamycin producing strain HDMNTE-01, determination method and the breeding of high yields producing strains were systematically researched in this paper.Firstly, the parameters of cylinder-plate method used to determine the Natamycin contents in zymotic fluid were difined. The results showed that after the amount of the sensitive strain, Saccharomyces cerevisiae W23, reached to 107CFU/mL by cultured, the two-tier flat-panel was prepared with 10% strain culture in the upper medium, and about 70μL detection liquid extracted by methanol was added into Oxford Cup, then the plate was cultured for 24 hours, so the results were desirable.The optimal cultural and preservative condition of HDMNTE-01 was difined by the comparison between six different slants and four different seminal media. The results showed: Spores slant medium (g /L) glucose 10 starch 10, yellow bean powder 10, malt extract 3 yeast extract 3, MgSO4 ? 7 H2 O 1, K2HPO4 0.5 NaCl 2, CaCO3 3, agar 20; seed Medium formula (g/L) starch 10 , yellow bean powder 10, peptone 6, corn pulp 6, glucose 10, MgSO4 ? 7 H2O 1, K2HPO4 0.5, NaCl 2, CaCO3 5.The shaking culture conditions of HDMNTE-01 were studied, including the effects of seed age, inoculum level, medium volume, the initial pH value, temperature, revolution on natamycin fermentation. The optimal fermentive condition was gained that inoculum concentration was 6%, liquid volume in flask was 25mL/50mL, the initial pH value was 7.0, temperature was 28℃, revolution is 220r/min, fermentive time was 96 hours.According to the biosynthetic pathway and metabolic regulation mechanism of Natamycin, HDMNTE-01 was mutated to screen the high-yield strains. The original strain was No.103 selected by agar block method. After the mutagenesis of Ultraviolet, DES, acridine orange, and complex mutagenesis of Ultraviolet and LiCl, 441 strains were obtained on the paltes contained Sodium acetate, sodium propionate and streptomycin sulfate. Finally, the high-yield strain was obtained by agar block method and determination of Natamycin, and named as F-99. The titer of F-99 was 1.78g/L , which was increased by 302% as compared with the original strain.