| Fosfomycin is a broad-spectrum antibiotic of a simple structure and small relative molecular weight. It can kill negative and positive bacteria of Gram. In recent years, its application has become more and more wide along with its gradually research deeply. However, its industrialization is still using the chemical synthesis methods, and the total yield is relatively lower, which is less than 35% at present. Through the chemical synthesis methods, the mixture of external rotation has a certain proportion of dextral-fosfomycin without activity which is not used effectively. Therefore it leads to high manufacturing costs and a certain amount of waste as well as polluting the environment. In this study, the strains conversing dextral-fosfomycin was screened and identified. And the optimum conversion conditions for the screened strain with higher conversion rate were conducted. It is an effective way to reduce production costs, to increase output and to reduce waste discharge by reutilizing dextral-fosfomycin.Five target strains with ability of conversing dextral-fosfomycin are obtained by high pressure screening mode.The conversion rates were 3.02%,6.51%,0.36%,2.78%,1.18% for each strain corresponding to Bacillus cereus sp. (B1), Bacillus amyloliquefaciens sp. (C1), Nocardia sp. (D2),Bacillus cereus sp. (El), Bacteria Propionibacterium sp. (F1).The conversion rate of Bacillus amyloliquefaciens increased to 7.69% comparing with the contrast of 6.51% under the optimum conversion conditions. The optimized culturing conditions are as follows:glucose of 14 g/L, peptone of 7 g/L, MgSO4.7H2O of 0.4 g/L, K2HPO4 of 0.8 g/L, NaCl of 1.33 g/L and CaCO3 of 0.8 g/L. The optimal fermentation conditions are as follows:culture temperature at 28 ℃, rotation speed at 150 r/min, fermentation starting pH 7.0 and the fermentation time at 72 h. |
