引入血红素生物合成基因对褐黄孢链霉菌产纳他霉素的影响

摘要

目的考察引入血红素合成关键基因对褐黄孢链霉菌生产纳他霉素的影响。　　方法运用 PCR方法扩增相关血红素合成基因hemA1、hemB、hemE，使用属间接合转移的方法转化入褐黄孢链霉菌 HCCB13086，获得引入血红素基因的工程菌株；通过摇瓶发酵考察突变菌株对载氧能力及纳他霉素产量的影响。　　结果成功构建3个引入血红素合成关键基因的菌株，3株菌在相对高氧条件下生长及产抗能力均与对照组相当，而在相对低氧条件下纳他霉素产量均较对照菌株提高，其中引入 hemA1血红素基因的菌株提高最为显著，较对照组的纳他霉素产量提高64%，达到8.52 g/L。　　结论引入血红素合成基因可提高菌体对氧的利用，促进菌体生长和代谢产物的增加。%Objective To investigate the effect of inducing key heme biosynthetic genes on natamycin production byStreptomyces gilvosporeus. Methods In order to induce heme genes, genes hemA1,B,E were PCR amplified and transformed intoStreptomyces gilvosporeus HCCB13086 by intergeneric conjugation transformation. The strain growth and natamycin yields of mutant strains under different dissolved oxygen levels were investigated through shaking flask fermentation. Results Three strains carrying key heme biosynthetic genes were successfully constructed. The natamycin yield of inducinghemA1 mutant was equal to the wild strain when fermented in relative high dissolved oxygen level flasks, while the yield was increased by 64%, reaching 8.52 g/L, under relatively low oxygen. Conclusion Inducing heme biosynthetic gene can raise the oxygen utilization and promote the strain growth and metabolite accumulation.