高产脂微生物-深黄被孢霉M018变株的选育及其油脂合成条件的研究

Breeding in Mortierella Isabellina Mutant M018 Capable of High Producing Lipid

以深黄被孢霉 (Mortierella isabellina) As3.341 0为出发菌株 ,经紫外线 (UV)、硫酸二乙酯 (DES)和亚硝基胍 (NTG)复合诱变处理 ,选育成功高产脂深黄被孢霉 M0 1 8变株 ,其摇瓶培养 ,菌体油脂含量达 65.6% ,比出发菌株提高 1 33%。60 m3罐三级发酵培养菌体油脂含量高达 79.2 % ,生物量达 37.8g/L。气相色谱分析表明变株 M0 1 8γ-亚麻酸的含量比出发菌株提高了 53%。连续传代试验表明 M0 1 8是一稳定的变株。该变株油脂合成的最佳碳源为葡萄糖 ,最佳氮源为酵母膏 ,最佳 C/N为40 0 :1 ,中温 (2 5～ 30℃ )适于菌丝生长 ,低温 (1 5～ 2 0℃ )适于细胞油脂合成。代谢曲线表明 M0 1 8变株是在培养基残氮极低时 。

A mutant strain M018 accumulating a large amount of lipid was successful obtained when the original strain Mortierella isabellina As3 3410 was treated by UV, DES, NTG as mutating agent. The content of lipid in M018 mycelium cultured in 500ml shaking flask was up to 65 5%, which was 2 33 times as much as that in the original strain mycelium, and the content of lipid in M018 mycelium cultured in 60 m 3 fermentor was up to 79 2% with biomass 37 8g/L. Analysis by gas chromatograph indicated content of γ linolenic existing in lipid from M018 mycelium was 7 2% which was 53% more than that from As3 3410 mycelium. Pass generation test showed that the heredity character of mutant M018 was stable. The optimal medium for M018 producing lipid was made up of glucose as carbon source and yeast extract as nitrogen source with C/N ratio 400∶1 Temperature 25～30℃ was suitable for M018 mycelium growing and 15～20℃ was more suitable for the mycelium producing lipid. The fermentation course curve showed that the mutant M018 began to rapidly convert glucose existing in fermentative medium into lipid when the content of nitrogen source was very low.