title: [Effect of overexpressing Nisin A structural gene nisA on Nisin A production].
abstract: Nisin is an antimicrobial peptide widely used in food industry. In this study, Nisin A production in Lactococcus lactis ATCC 11454 was improved by overexpression of Nisin A structural gene nisA through introducing a shuttle expression vector pMG36ek-nisA and an integrated vector pDG780-nisA into the host strain. The differences of growth profiles and Nisin A production level between the two obtained genetic engineering strains FMM1/FMM2 and the parent strain were investigated. Our results show that while the growth profile (the growth rate, biomass and pH) of FMM1 was similar to the parent strain, its Nisin A production increased 31%. In contrast, the biomass of FMM2 was notably lower than the parent strain, while its yield of Nisin A enhanced slightly. The transcription level of genes involved in Nisin A biosynthesis in both engineering strains was further detected by RT-PCR. We found that all the 11 Nisin A biosynthetic genes in FMM1 and FMM2 had a higher transcription level than those in the parent strain, and these genes exhibited more significant increasing degree of transcription level in FMM1 which hosted the autonomous replicating nisA gene. These data suggest that expression of nisA may act as a rate-limit factor in Nisin A biosynthesis. In conclusion, this work provides a new method to improve Nisin A production by increasing the transcription level of nisA, paving the way to further large-scale industrial production of Nisin A.
authors: State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, Hubei, China.
authors: Miaomiao
authors: M
authors: Fan
authors: Yimin
authors: Y
authors: Qiu
authors: Chen
authors: C
authors: Liu
authors: Zhixia
authors: Z
authors: Ji
authors: Xin
authors: X
authors: Ma
authors: Yi
authors: Y
authors: Yu
authors: Shouwen
authors: S
authors: Chen
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D005798:Genes, Bacterial; D005818:Genetic Engineering; D005822:Genetic Vectors; D013294:Lactococcus lactis / Q000235:genetics* / Q000378:metabolism; D009561:Nisin / Q000096:biosynthesis* / Q000235:genetics; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D009561:Nisin; C102526:nisin A