乳链菌肽自身免疫基因nisI的表达对乳链菌肽产量的影响  

Enhanced nisin production by overexpression of nisin immunity gene nisI in the nisin-producing strain

作　　者：胡红梅[1,2] 蒋立科[1] 林宇恒[2] 还连栋[2] 钟瑾[2] 

机构地区：[1]安徽农业大学生命科学学院,合肥230036 [2]中国科学院微生物研究所,北京100101

出　　处：《微生物学报》2010年第10期1341-1346,共6页Acta Microbiologica Sinica

基　　金：国家"863计划"(2006AA10Z319);中国科学院知识创新重要方向项目(KSCX2-YW-G-016)~~

摘　　要：【目的】通过基因工程手段增加乳链菌肽(nisin)自身免疫基因nisI在nisin产生菌Lactococcus lactisNZ9800/pHJ201中的表达水平,增强该菌对nisin的抗性,从而达到提高nisin产量的目的。【方法】将带有强组成型启动子P59的免疫基因nisI克隆到nisin表达质粒pHJ201上,将重组质粒引入L.lactis NZ9800中,使nisI基因过量表达,得到重组菌株L.lactis NZ9800/pHMI,并比较该重组菌株与对照菌株L.lactis NZ9800/pHJ201的生长曲线、对nisin的抗性水平、抑菌活性及nisin产量的差异。【结果】nisI的表达对重组菌的生长速度没有明显的影响,却能促使重组菌株对nisin的抗性水平提高25%、在发酵6h和8h时,nisin的产量分别提高32%和25%。【结论】增加乳链菌肽自身免疫基因nisI的表达可以提高产生菌对nisin的抗性,从而提高乳链菌肽产量。[ Objective] Our aim was to enhance nisin production by overexpression of nisin immunity gene nisI in nisinproducing strains. [ Methods] Nisin immunity gene nisl with a strong promoter P59 was cloned into vector pHJ201 and introduced into Lacotococcus lactis NZ9800, resulting in a recombinant strain L. lactis NZ9800/pHMI. Then the differences between the recombinant strain and the control strain L. lactis NZ9800/pHJ201 were analyzed in several aspects, including their growth curves, nisin resistance level and antibacterial activity against indicator strain Microccus flavus NCIB 8166. [ Results] The overexpression of nisl had no significant difference in growth rate between recombinant strain and contrast strain. However, it promoted recombinant strain tolerance 25% higer nisin resistance level and stronger antibacterial activity against M. flavus NCIB 8166, which was increased by 32% and 25% when fermented for 6 and 8 hours, respectively. [ Conclusion] These results indicated that overexpression of nisl gene in the nisin producing strain can effectively enhance nisin resistence level and thus improve nisin production.

关 键 词：乳链菌肽 免疫基因nisI 抑菌活性 抗性水平 

分 类 号：Q93[生物学—微生物学]