Identification and Isolation of an Enterocin Encoding Gene from an Enterococcus faecium Strain LUB950217 Isolated from Oak Tree Sap

Lactic acid bacteria )LAB) are a group of gram-positive, non-spore forming, cocci or rod shaped, catalase-negative organisms, which are generally recognized as safe (GRAS). The LAB can cause changes in the food flavor and texture. Enterococci are a group of LAB capable of producing antimicrobial peptides.

This experimental study was conducted to identify and isolate genes encoding antimicrobial peptides from an E. faecium LUB950217 strains isolated from oak tree. In doing so, genomic DNA was extracted from E. faecium strains and polymerase chain reaction (PCR) analysis was performed using specific primers. Amplified PCR products were sequenced by Sanger sequencing. Bioinformatic analysis was carried out and the peptide was modeled. Both DNA and protein Blast search confirmed that the PCR product encoded an antimicrobial peptide, known as LUB950217 enterocin with 36 amino acids of 4658.28 Da molecular mass. The isolated enterocin peptide had 86-100% similarity to other known enterocins in the peptide data bases. The LUB950217 enterocin was almost water insoluble and it was found to be cationic (2.2, pH=7). The LUB950217 enterocin seems to inhibit both gram-positive and gram-negative bacteria growth in vitro, suggesting LUB950217 enterocin can be used in food stuff and animal feed. Furthermore, isolation, cloning, and expression of this peptide may render resistance to fungi and bacteria pathogens in crop plants.