Superior esterolytic activity in environmental Lactococcus lactis strains is linked to the presence of the SGNH hydrolase family of esterases
Résumé
We investigated the esterolytic activity of dairy- and environment-derived Lactococcus lactis strains through a
quantitative esterase assay based on hydrolysis of p-nitrophenyl dodecanoate (PNP). In general, environmental
L. lactis strains had higher esterolytic activity than dairy strains. Comparative genome analysis revealed the
presence of an open reading frame related to esterolytic activity in the environmental strain L. lactis DPC6855
(from corn), encoding the predicted product SGNH/GDSL hydrolase family protein. The 1,287-bp gene encodes
a 428-amino acid SGNH/GDSL hydrolase. The presence of this gene in most of the environment-derived strains
was established by PCR; the gene was not found in the genome of L. lactis DPC6853 or in genomes of L. lactis
strains from dairy sources, suggesting a possible correlation between the SGNH hydrolase family and higher
esterolytic activity. This work provides further evidence of more diverse genotypic and phenotypic traits in
environmental compared with dairy L. lactis strains.
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