Characterization and antimicrobial activity of natural isolate Lactococcus lactis subsp. lactis BGSM1-19
2007
Strahinic, I. | Cvetanovic, D. | Kojic, M. | Fira, Dj. | Tolinacki, M. | Topisirovic, Lj., Institute of Molecular Genetics and Genetic Engineering, Belgrade (Serbia)
The strain Lactococcus lactis subsp. lactis BGSM1-19, isolated from traditionally homemade white cheese, produces two bacteriocins: lactococcin B-like bacteriocin named bacteriocin BacSMa and bacteriocin BacSMb which have shown similarity with lacticin RM. Plasmid curing resulted in a low yield (0.33%) of some derivatives. The bacteriocin biosynthesis was observed in the logarithmic phase of growth and the production plateau was reached after 8 h of incubation at 30 deg C, when the culture entered the early stationary phase. Biochemical characterization showed that strain BGSM1-19 retained antimicrobial activity within the pH range of 1 to 12 or after treatment at 100 deg C for 15 min. However, bacteriocin activity was completely lost after teatment with different proteolytic enzymes. The strain BGSM1-19 contains five plasmids. Plasmid curing indicated that genes coding for bacteriocins synthesis and immunity seem to be located on plasmids. BGSM1-19 exhibited antimicrobial activity against some pathogenic bacteria such as Salmonella paratyphi, Micrococcus flavus, Pseudomonas aeruginosa and Staphylococcus aureus.
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