Premium
Enhancement of nisin production in milk by conjugal transfer of the protease‐lactose plasmid pLP712 to the wild strain Lactococcus lactis UQ2
Author(s) -
GARCÍAPARRA MARÍA D,
CAMPELO ANA B,
GARCÍAALMENDÁREZ BLANCA E,
REGALADO CARLOS,
RODRÍGUEZ ANA,
MARTÍNEZ BEATRIZ
Publication year - 2010
Publication title -
international journal of dairy technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.061
H-Index - 53
eISSN - 1471-0307
pISSN - 1364-727X
DOI - 10.1111/j.1471-0307.2010.00618.x
Subject(s) - nisin , lactococcus lactis , lactose , strain (injury) , plasmid , microbiology and biotechnology , biology , streptococcaceae , food science , cheesemaking , chemistry , bacteria , biochemistry , dna , lactic acid , antibiotics , antimicrobial , genetics , anatomy
Lactococcus lactis UQ2 is a wild nisin A producer isolated from a Mexican cheese that grows poorly in milk. Conjugal matings with L. lactis NCDO712 to transfer the Lac+ Prt+ plasmid pLP712 and selection with nisin and lactose yielded L. lactis NCDO712 NisA+. Naturally rifampicin resistant L. lactis UQ2Rif was isolated to provide an additional selective marker. The identity of a transconjugant L. lactis UQ2Rif Lac+ was confirmed by RAPD‐PCR fingerprinting, nisA PCR amplification, nisin production, presence of pLP712 and phospho‐β‐galactosidase activity. This strain performed well in milk and synthesised 200 IU/mL nisin, 40 times more than the original strain.