Saccharomyces cerevisiae B9发酵生产S-腺苷甲硫氨酸的优化研究

Optimization of Sadenosylethionine Production by Saccharomyces cerevisiae B9

以高产S-腺苷甲硫氨酸的菌株Saccharomyces cerevisiaeB9对培养基和发酵条件进行了优化研究。通过单因素水平测试和正交水平测试,确定了发酵培养基的最佳配方组合为:蔗糖8%、NH4Cl 0.5%、NH4H2PO40.2%、酵母提取物1.2%、MgSO4.7H2O 0.01%、KH2PO40.6%、L-甲硫氨酸1.2%,与原始发酵培养基相比,S-腺苷甲硫氨酸从1.16 g/L提高到3.35 g/L,菌体干重从16.18 g/L提高到18.25 g/L。在此基础上,对发酵条件进行优化,结果发现:初始pH5,培养温度30℃,摇床转速180 r/min为最佳培养条件。此时,菌体干重达19.86 g/L,S-腺苷甲硫氨酸产率达4.2 g/L。

The optimum medium compositions and culture conditions were carried out on Saccharomyces cerevisiae B9 with high activity of S-adenosylmethionine. The optimum carbon source and nitrogen source were evaluated first. The concentrations of inorganic salt,yeast extracted and the precursor inductor of L- methionine were also determined. Afterwards, by the orthogonal experiment, the optimi zation concentrations of fermentation medium compositions were determined as follows, sucrose 8%, NH4Cl 0. 5%,NH4H2PO4 0. 2%,yeast soaked 1. 2% ,MgSO4 ·7H2O 0.1%,KH2PO4 0.6% ,L-methionine 1.2%. Under the optimum medium,in contrast with primitive fermentation medium, the yield of S- adenosylmethionine increased from 1. 16 g/L to 3. 35 g/L, mycelium dry weight increased from 16. 18 g/L to 18. 25 g/L. Experiments of the optimization on other fermentation conditions were also carried out based on the above, the result showed that. initial pH = 5, temperature 30℃, table rotational speed 180 r/min,under the optimization condition,the yield of S-adenosylmethionine was as high as 4. 2 g/L, mycelium dry weight was as high as 19. 86 g/L.