等离子体作用结合氧限制模型选育利福霉素SV高产菌株

利福霉素SV毒性低、疗效高、抗菌谱广,主要由地中海拟无枝酸菌发酵生产,其发酵过程属于耗氧发酵,供氧直接影响产物形成。为减少发酵过程氧限制影响,进一步提高利福霉素发酵产量,通过构建定向氧限制模型,将常温常压等离子体诱变和无水亚硫酸钠氧限制筛选模型相结合,建立了利福霉素生产菌株24孔板快速培养的高通量筛选方法,高效选育出能够耐受低氧环境的利福霉素SV高产菌株NSMXG-M126,发酵代谢状态参数变化显示,该高产菌株具有更好的氧亲和力。同样的供氧条件下,与对照相比表现出较快的菌体生长速率和利福霉素SV的快速合成能力。在低供氧情况下发酵单位达到7839mg/L,较出发菌株提高48%,表明耐受低氧的突变菌株具有更高的利福霉素SV生产效率。

Breeding of High-yield Rifamycin SV Strain by Plasma Action Combined with Oxygen Restriction Model

Rifamycin SV has low toxicity,high curative effect,and broad antibacterial spectrum.It is mainly produced through the aerobic fermentation by Amycobacterium marinum,and oxygen supply limitation was always the critical factor that affects the rifamycin SV biosynthesis.In order to reduce the influence of oxygen limitation in the fermentation process and further increase the fermentation yield of rifamycin,an oxygen limitation directional model was established with anhydrous sodium sulfite,combining normal temperature and atmospheric pressure plasma mutagenesis(ARTP);a high-throughput screening method of rapid culture of the vinegarproducing strains in 24-well plates was proposed;the high-yielding rifamycin SV strain NSMXG-M126 that can tolerate hypoxia has been efficiently selected.The changes in the parameters of the fermentation metabolic state show that the high-yielding strain has better oxygen affinity.Under the same oxygen supply conditions,it showed a faster bacterial growth rate and rapid synthesis of rifamycin SV compared with the control.In the case of low oxygen supply,the fermentation unit reached 7839 mg/m L,which was 48%higher than the original strain.The results demonstrated that the mutant strains that tolerate hypoxia have higher production efficiency of rifamycin SV.