In situ activity of a bacteriocin-producing Lactococcus lactis strain. Influence on the interactions between lactic acid bacteria during sourdough fermentation.
OBJECTIVE
To biochemically characterize the bacteriocin produced by Lactococcus lactis ssp. lactis M30 and demonstrate its effect on lactic acid bacteria (LAB) during sourdough propagation.


RESULTS
A two-peptide bacteriocin produced by L. lactis ssp. lactis M30 was purified by ion exchange, hydrophobic interaction and reversed phase chromatography. Mass spectrometry of the two peptides and sequence analysis of the ltnA2 gene showed that the bacteriocin was almost identical to lacticin 3147. During a 20-day period of sourdough propagation the stability of L. lactis M30 was demonstrated, with concomitant inhibition of the indicator strain Lactobacillus plantarum 20, as well as the non-interference with the growth of the starter strain Lact. sanfranciscensis CB1.


CONCLUSIONS
In situ active bacteriocins influence the microbial consortium of sourdough LAB and can "support" the dominance of insensitive strains during sourdough fermentation.


CONCLUSIONS
The in situ bacteriocinogenic activity of selected lactococci enables the persistence of insensitive Lact. sanfranciscensis strains, useful to confer good characteristics to the dough, at a higher cell concentration with respect to other LAB of the same ecosystem.
Settanni
L
L
Dipartimento di Scienze degli Alimenti, Sezione di Tecnologie e Biotecnologie degli Alimenti, Università degli Studi di Perugia, Perugia, Italy.
Massitti
O
O
Van Sinderen
D
D
Corsetti
A
A
D000900:Anti-Bacterial Agents / Q000096:biosynthesis* / Q000302:isolation & purification / Q000494:pharmacology; D001430:Bacteriocins / Q000096:biosynthesis* / Q000235:genetics / Q000302:isolation & purification / Q000494:pharmacology; D001939:Bread / Q000382:microbiology*; D015169:Colony Count, Microbial / Q000379:methods; D003470:Culture Media; D004269:DNA, Bacterial / Q000235:genetics; D005285:Fermentation; D005516:Food Microbiology; D005798:Genes, Bacterial / Q000235:genetics; D007778:Lactobacillus / Q000187:drug effects / Q000254:growth & development*; D048191:Lactiplantibacillus plantarum / Q000187:drug effects / Q000254:growth & development; D013294:Lactococcus lactis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D016133:Polymerase Chain Reaction / Q000379:methods; D017422:Sequence Analysis, DNA / Q000379:methods
D000900:Anti-Bacterial Agents; D001430:Bacteriocins; D003470:Culture Media; D004269:DNA, Bacterial; C082508:lacticin 481