Production Of Natamycin By Streptomyces Gilvosporeus

Natamycin,which is an efficient,safe,broad-spectrum and a polyene macrolide antifungal antibiotic and as food preservatives and medicine widely used in food and medicine field.But the low level of natamycin production,makes the production cost is high,so that his former application is restricted.Therefore,it is necessary to pay attention to study natamycin fermentation production.In this work,in order to improve yield and quality of natamycin,breeding high-yield strains,optimization of fermentation process and extraction process were investigated.The main results are summarized as follows.(1)A mutant strain ZM701-66 with high natamycin yield was obtained by the mutagenetic treatments of ultra violet(UV)and atmospheric and room temperature plasma(ARTP)on the basis of a strain ZQ701-3 which was stored in our laboratory.After the mutagenesis,the natamycin yield of mutant strain ZM701-66 could reach 3.03 g/L and the increase was 175% compared with the original strain.(2)To improve the natamycin-producing ability of strain ZM701-66,fermentation process of natamycin in shake was optimized by single factor test,response surface methodology(RSM).The optimal fermentation culture medium were determined(glucose 52.6 g/L,peptone 3.0 g/L,soybean meal 23.3 g/L,MgSO4 2.0 g/L,CaCO3 3.2 g/L,The optimal fermentation condition: temperature 28°C,inoculum size 8%,inoculum ages 22 h,fluid volume 40 m L/500 m L,the speed of 200 r/min,fermentation time 84 h).In the optimal fermentation medium and fermentation conditions,the maximum yield of natamycin is 5.73 g/L,the original strains,natamycin yield increased by 89.4%.(3)Based on natamycin shaking flask fermentation experiments,the added sugar experiment was performed in 10-liter fermentor.When the sugar concentration was maintained above 25 g/L,fermentation period 96 h,The yield of natamycin from 5.83 to 6.56 g/L,which is increased by 12.5%.(4)The extraction conditions of natamycin from fementation was researched.The optimized extraction conditions were as follows: 75% methanol,the ratio of 75% methanol to be the wet cell weight 8:1(m L:g),pH 10,indoor temperature,and the extraction time 1 h,the resulting recovery rate of 85%,degree of purity of 83.6%.In the of process of extraction,natamycin biological activity was not affected.