在吸水链霉菌中表达透明颤菌血红蛋白基因提高子囊霉素产量

Enhancement of Ascomycin Production by Expression of Vitreoscilla Hemoglobin Gene in Streptomyces hygroscopicus

为了解决子囊霉素(1)发酵过程低溶氧的问题,本研究将透明颤菌(Vitreoscilla)血红蛋白基因(vgb)整合至1生产菌株吸水链霉菌(Streptomyces hygroscopicus)中,构建工程菌SIPI-FK520-2,通过RT-PCR分析检测到了vgb基因的转录表达,进一步利用CO结合差光谱分析也证实了工程菌中透明颤菌血红蛋白(VHb)具有生物活性。最后在发酵罐进行该工程菌的发酵培养研究,结果表明,与野生菌相比,工程菌发酵过程溶氧水平明显改善,1产量提高了38%,达到1 269.7 mg/L。

In order to solve the shortage of dissolved oxygen in the fermentation process of ascomycin （1）,the Vitreoscilla hemoglobin gene （vgb） which encodes Vitreoscilla hemoglobin （VHb） was integrated into 1 producing strain Streptomyces hygroscopicus. The codon-optimized vgb gene was ligased with plasmid pSET-M, making it under the control of constitutive erythromycin resistance gene promoter （ermE＊）, to yield an recombinant plasmid pSET-vgb.Then, vgb gene was introduced into the genome of S. hygroscopicus SIPI-FK520-1 through conjugal transfer to construct an engineering strain named SIPI-FK520-2. The RT-PCR analysis showed that vgb gene had been successfully expressed in the recombinant engineering strain. The biological activity of VHb in the recombinant strain was further detected and confirmed by CO-binding difference spectroscopy. Finally, the strain was cultured in a 5 L bioreactor. The results indicated that the level of dissolved oxygen in fermentation process was significantly improved, and the yield of 1 was increased by 38% compared to the wild strain, up to 1 269.7 mg/L.