Conjugal transfer of bacteriocin plasmids from different genera of lactic acid bacteria into Enterococcus faecalis JH2-2

The lactic acid bacteria (LAB) are of great interest
because of their food grade quality and industrial importance.
In the recent past, the pediocin PA-1 like bacteriocin was
found to be synthesized in cross-species and cross-genera.
Hence, the present work was carried out in order to determine
the transfer of plasmid encoded pediocin PA-1 like bacteriocin
among LAB. The objective of this study is to demonstrate the
dissemination of bacteriocin-encoded plasmid from
Pediococcus acidilactici NCIM 5424, Enterococcus faecium
NCIM 5423 and Lactobacillus plantarum Acr2 to
Enterococcus faecalis JH2-2 under in vitro (filter mating
method) and in situ (soymilk model) conditions. The fermentation
of the soymilk was determined by the selected pediocin
producers. E. faecium NCIM 5423 was able to transfer the
bacteriocin only under in situ conditions, whereas the native
pediocin producer P. acidilactici NCIM 5424 transferred the
bacteriocin under both the methods used. The in situ method
gave more transfer frequency, ranging from 10−7 to 10−4
transconjugants per recipient cell. No conjugal transfer by L.
plantarum Acr2 was observed. The physiological conditions
like pH and temperature were found to influence the production
of bacteriocin in the obtained transconjugants. The results
suggest the horizontal gene transfer (HGT) and the natural
spread of pediocin PA-1-like bacteriocin among LAB present
in their close vicinity by means of conjugation. The dissemination
of pediocin PA-1-like bacteriocin under in situ conditions
is noteworthy, and such bacteriocin producers can be
useful in the fermentation of dairy products and construction
of novel cultures.