Genomic and Proteomic Characterization of Bacteriocin-ProducingLeuconostoc mesenteroidesStrains Isolated from Raw Camel Milk in Two Southwest Algerian Arid Zones

Abstract

Information on the microbiology of camel milk is very limited. In this work, the genetic characterization and proteomic identification of 13 putative producing bacteriocinLeuconostocstrains exhibiting antilisterial activity and isolated from camel milk were performed. DNA sequencing of the 13 selected strains revealed high homology among the 16S rRNA genes for all strains. In addition, 99% homology withLeuconostoc mesenteroideswas observed when these sequences were analysed by the BLAST tool against other sequences from reference strains deposited in the Genbank. Furthermore, the isolates were characterized by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDITOF MS) which allowed for the identification of 2 mass peaks 6242 m/z and 5118 m/z that resulted to be specific to the speciesL. mesenteroides. Remarkably, the phyloproteomic tree provided more intraspecific information ofL. mesenteroidesthan phylogenetic analysis. Accordingly, phyloproteomic analysis groupedL. mesenteroidesstrains into different subbranches, while allL. mesenteroidesisolates were grouped in the same branch according to phylogenetic analysis. This study represents, to our knowledge, the first report on the use of MALDI-TOF MS on the identification of LAB isolated from camel milk.