A Lactococcus lactis subsp. lactis strain (L. lactis 69) capable to produce a heat-stable bacteriocin was isolated
from charqui, a Brazilian fermented, salted and sun-dried meat product. The bacteriocin inhibited, in vitro,
Listeria monocytogenes, Staphylococcus aureus, several lactic acid bacteria isolated from foods and spoilage
halotolerant bacteria isolated from charqui. The activity of the bacteriocin was not affected by pH (2.0–
10.0), heating (100 °C), and chemical agents (1% w/v). Treatment of growing cells of L. monocytogenes ScottA
with the cell-free supernatant of L. lactis 69 resulted in complete cell inactivation. L. lactis 69 harbored the
gene for the production of a nisin-like bacteriocin, and the amino acid sequence of the active peptide was
identical to sequences previously described for nisin Z. However, differences were observed regarding the
leader peptide. Besides, the isolate was able to survive and produce bacteriocins in culture medium with
NaCl content up to 20%, evidencing a potential application as an additional hurdle in the preservation of
charqui.
A Lactococcus lactis subsp. lactis strain (L. lactis 69) capable to produce a heat-stable bacteriocin was isolated
from charqui, a Brazilian fermented, salted and sun-dried meat product. The bacteriocin inhibited, in vitro,
Listeria monocytogenes, Staphylococcus aureus, several lactic acid bacteria isolated from foods and spoilage
halotolerant bacteria isolated from charqui. The activity of the bacteriocin was not affected by pH (2.0–
10.0), heating (100 °C), and chemical agents (1% w/v). Treatment of growing cells of L. monocytogenes ScottA
with the cell-free supernatant of L. lactis 69 resulted in complete cell inactivation. L. lactis 69 harbored the
gene for the production of a nisin-like bacteriocin, and the amino acid sequence of the active peptide was
identical to sequences previously described for nisin Z. However, differences were observed regarding the
leader peptide. Besides, the isolate was able to survive and produce bacteriocins in culture medium with
NaCl content up to 20%, evidencing a potential application as an additional hurdle in the preservation of
charqui.
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