Studies On Mutation And Screening Of Strains Producing Natamycin

Natamycin serves as a broad-spectrum antifungal (fungistatic and fungicid) agent. It can effectively inhibit mold and yeast growth, and has no toxic effects even at high levels of ingestion on mammalian species. Therefore natamycin is effective in the therapy of fungus infections of eyes and in protection of foods from mold and yeast growth.The article quested for some studies on the strain improvement, and finishined the following jobs.Established a relation between streptomycin resistance and natamycin yield. And established a method to determining natamycin in fermentation broth using UV spectrophotometer which are fast and effective.A stable and high-yielding strain SG-17 was obtained from SG-S strain of natamycin producer Streptomyces gilvosporeus by stable experimentation. SG-17 strain was mutated by three methods UV, microwave, ⁶⁰Co-γirradiation. The results showed that three mutation methods could enhance the fermentation ability of trains. The natamycin yield of the high-yielding mutant strains UV-125,M-63,γ-188 were increased by 59%,33%,16% respectively compared with their parent strains. The yield ofγ-188 strain was 4.58μg/mL, 1.45 taller than SG-17.Besides, the fermentation conditions of natamycin were studied in shaking flask. First, we explored the influence of different carbon source, nitrogen source, inorganic salt and precursor on natamycin production. On orthogonality experiment basis through statistical analysis, the optimum medium was determined, and the natamycin yield improved by 12%. What was more, we researched the temperature, pH value, the volume of vaccination, and found that the container of 25mL, pH value of 7.2, the temperature of 28℃, natamycin yield was the highest.