Influence of pH on growth and bacteriocin production by Lactococcus lactis subsp. lactis 14ONWC during batch fermentation

1994 ◽  
Vol 41 (4) ◽  
pp. 388-394
Author(s):  
E. Parente ◽  
A. Ricciardi ◽  
G. Addario
2007 ◽  
Vol 3 (1) ◽  
pp. 49-54 ◽  
Author(s):  
Archana Kumari ◽  
Amar P. Garg ◽  
Kousar Makeen ◽  
Mohan Lal ◽  
Charu Gupta ◽  
...  

2013 ◽  
Vol 19 (No. 5) ◽  
pp. 171-176 ◽  
Author(s):  
T.M. Do ◽  
M. Plocková ◽  
J. Chumchalová

Screening for bacteriocin production of 60 strains of lactic acid bacteria (LAB) both isolated from various Vietnamese fermented food and obtained from the culture collection resulted in the detection of a bacteriocin-producing strain, Lactococcus lactis subsp. lactis LTM 32 isolated from Vietnamese fermented milk. This strain was identified and partly characterized. This bacteriocin inhibited not only closely relative strains of LAB but also strains of Listeria monocytogenes, Bacillus sp. including B. cereus, B. stearothermophilus, B. subtilis, B. pumilus and Staphylococcus aureus. It was heat stable at 121°C for 15 min, at 100°C for 120 min and stable during storage at –20°C and 4°C for 3 months. The bacteriocin was inactivated by some proteolytic enzymes, namely by proteinase K and pronase E in concentrations up to 0.5 mg/ml but not by  α-amylase and pepsin. The optimal growth and bacteriocin production were achieved in M17L broth at 30°C and initial pH 6.8. The characteristics of bacteriocin-producing strain Lactococcus lactis subsp. lactis LTM 32 are of interest for food safety.


2006 ◽  
Vol 52 (11) ◽  
pp. 1110-1120 ◽  
Author(s):  
Milan Kojic ◽  
Ivana Strahinic ◽  
Djordje Fira ◽  
Branko Jovcic ◽  
Ljubisa Topisirovic

In this study, the plasmid content and bacteriocin production of natural isolates of lactococci were investigated. Five bacteriocin producing lactococcal strains (Lactococcus lactis subsp. lactis BGMN1-2, BGMN1-3, BGMN1-5, BGMN1-6, and BGMN2-7) were isolated as nonstarter microflora of semi-hard homemade cheese and characterized. All isolates contained a number of plasmids. It was shown that lcnB structural genes for bacteriocin lactococcin B were located on large plasmids in all isolates. In the strains BGMN1-3 and BGMN1-5 proteinase prtP genes collocated with lcnB. Furthermore, these strains produced two additional bacteriocins (LsbA and LsbB) with genes responsible for their production and immunity located on the small rolling circle-replicating plasmid pMN5. Using deletion experiments of pMN5, minimal replicon of the plasmid and involvement of a bacteriocin locus in plasmid maintenance were identified. In addition, plasmid curing experiments showed that genes for catabolism or transport of 10 carbohydrates in the strain BGMN1-5 were plasmid located.Key words: lactococci, natural isolates, bacteriocin, plasmid curing.


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