title: [Effect of 6-phosphofructokinase gene-pfk overexpression on nisin production in Lactococcus lactis N8].
abstract: OBJECTIVE
  To accelerate the formation of nisin through overexpressing 6-phosphofructokinase gene pfk in nisin-producer Lactococcus lactis N8.
  
  
  METHODS
  The genes of pfk and pkaC encoding the catalytic subunit of cAMP-dependent protein kinase were cloned into the vector pMG36e andtransformed into L. lactis N8, resulting in the recombinant strain L. lactis N8-pMG36e-pfk-pkaC. Several biochemical and physological factors, including growth profiles, activity of 6-phosphofructokinase, expression of nisA , antibacterial activity of supernatants and nisin titer, were monitored to investigate the differences between the recombinant strain and the parental strain.
  
  
  RESULTS
  No significant difference was observed with respect to the growth patterns of the recombinant strain and the wild type. As expected, the biological activity of PFK in recombinant strain was increased for all examined samples. Correspondingly, the yield of nisin was increased by 20% in the recombinant strain after fermentation for 10 hours, which could be attributed to the accelerated biosynthesis of nisin. As a result, the fermentation cycle was reduced about 2 hours. Meanwhile, different concentration of glucose did not affect the formation of nisin.
  
  
  CONCLUSIONS
  The overexpression of pfk and pkaC genes in the nisin-producer strain can effectively accelerate nisin biosynthesis.
authors.forename: Duolong
authors.initials: D
authors.lastname: Zhu
authors.forename: Kai
authors.initials: K
authors.lastname: Zhao
authors.forename: Haijin
authors.initials: H
authors.lastname: Xu
authors.forename: Yanling
authors.initials: Y
authors.lastname: Bai
authors.forename: Xiuming
authors.initials: X
authors.lastname: Zhang
authors.forename: Mingqiang
authors.initials: M
authors.lastname: Qiao
mesh_terms: D000900:Anti-Bacterial Agents / Q000096:biosynthesis*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D005285:Fermentation; D015964:Gene Expression Regulation, Bacterial; D005822:Genetic Vectors / Q000235:genetics / Q000378:metabolism; D013294:Lactococcus lactis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D009561:Nisin / Q000096:biosynthesis*; D025221:Phosphofructokinases / Q000235:genetics* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D009561:Nisin; D025221:Phosphofructokinases