Insights Into The Broad Antibacterial Spectrum Of Bacteriocin Isolated From Probiotic Lactobacillus Fermentum LMEM22 Strain

Abstract

This communication aims to validate the probiotic attributes of the Lactobacillus fermentum LMEM22 strain, safety profiling, 16S rRNA gene sequence analysis, and bacteriocin characterization. The bacteriocin of 13.1 kDa (based on the glycine-SDS-PAGE analysis) was isolated from L. fermentum LMEM22 curd strain (NCBI GenBank with accession No. MH380182), the identity for which was confirmed by 16S rRNA gene sequence analysis. The probiotic properties and safety profiles were authenticated in vitro systems. The zone diameter of inhibition from the L. fermentum LMEM22 bacteriocin action, following agar-well diffusion, ranged 19 – 23 mm and 17 – 24 mm, respectively, for gram-negative and gram-positive bacteria. On enzymatic treatment with proteinase K and trypsin the bacteriocin lost the bacterial growth inhibition capacity, and it was found insensitive against α-amylase action, authenticating its proteinaceous nature. The γ-haemolytic L. fermentum LMEM22 strain, for which gelatinase and DNase activities were negative, had tolerance to high sodium chloride concentration range (2 – 6.5%), low pH (2 – 4%), and bile salts (0.125 – 0.5%). This study, thus, authenticated the probiotic attributes of L. fermentum LMEM22 strain for safe consumption by the people, and the usefulness of bacteriocin isolated, as a valued protein antibiotic for the prevention and treatment of multidrug resistant bacterial infection.