MINING BIOTECHNOLOGICAL PROPERTIES IN Enterococcus mundtii CRL35 GENOMIC DATA

BONACINA JULIETA; SUAREZ NADIA E; SESMA FERNANDO ; SAAVEDRA LUCILA

Tucumán

Simposio; SIBAL; 2013

Centro Referencia para Lactobacilos

Until recently, classical methods based on phenotypic and physiological traits have been used to select the most performing strains in the food industry; however with the increasing availability of bacterial genome sequences, in silico screening strategies may now be employed to the same end. Enterococcus mundtii CRL35 is a bacteriocinogenic non-starter LAB strain isolated from an artisanal cheese. Its genome has been recently sequenced using a whole-genome shotgun (WGS) strategy with a 454 GS Titanium pyrosequencer at the Instituto de Agrobiotecnología de Rosario (INDEAR), Argentina. The draft genome sequence consists of 2.867.684 bp with a mean GC content of 37.98 ± 4.74 %, a total of 2.778 coding sequences (CDS), and 58 structural RNAs (55 tRNAs) predicted. The purpose of the present work was to perform an in silico genomic screening of biotechnological properties presents in E. mundtii CRL35. Genomic analysis were done using the RAST annotation Server, Blast algorithms, ISGA and KEGG databases. Results obtained with RAST showed that there are 305 subsystems denoted in the chromosome which represents only 40% of the sequences assigned. Since Lactic Acid Bacteria are associated with the production of practically all dairy fermented foods, they need major adaptations to dairy environments. In this sense E. mundtii CRL35 genome contain genes for lactose utilization (PTS Lac; LacZ), oligopeptide transport systems (oppA, oppB, oppC, oppD, oppF), aminopeptidase S (Leu, Val, Phe, Tyr preference), isoaspartyl dipeptidase (Asp-X-specific dipeptidase), aminopeptidase C (pepC), proline dipeptidase, methionine aminopeptidase, and aminopeptidase YpdF. In addition, considering that a better aroma is also a desire feature, a set of genes related to lipase and esterase activities such as GDSL-like lipase/acylhydrolase, phospholipase D, tributyrin esterase, glycerophosphoryl diester phosphodiesterase, acyl-ACP thioesterase and phospholipase/Carboxylesterase were localized. A NADP-specific glutamate dehydrogenase was located in contig 3, and no genes encoding for nitrate and nitrite reductase activity were found. On the other hand, we detected genes encoding tyrosine (tdc) and lysine (ldc) decarboxylases that convert tyrosine to tyramine, and lysine to cadaverine respectively, but not those that participate in the production of putrescine (odc) and histamine (hdc). The genome sequence study also confirmed the presence of enterocin CRL35 biosynthetic cluster and BAGEL 3 software analysis demonstrates that this would be the only bacteriocin cluster present in E. mundtii CRL35 genome. Further experimental work is necessary to evaluate if encoding traits are responsible for the adaptability of this strains to dairy environments.