Therapeutic intervention and molecular characterizations of bacteriocin producing Lysinibacillus sp., nov., isolated...

Many bacteriocins from Lactobacilli have been reported as immunostimulatory, preservatives, anticancerous and biocontroling. However, antimicrobial potential of Lysinibacillus is not much reported. In this study, an attempt was made to isolate and anticipate therapeutic potential of Lysinibacillus from spoiled food sample. We screened 125 Lactobacilli for their antagonistic nature against food borne and disease causing bacterial and fungal pathogens. Among them, one Bacillus was phenotypically, and 16S rRNA based, molecularly identified as Lysinibacillus species given with accession numbers JX416855 in NCBI. The type strain JX416855 has shown the 99% identity with the Lysinibacillus fusiformis, Lysinibacillus sphaericus and Lysinibacillus xylanilyticus. It was amylase, protease, gelatinase, nitrate reductase and urease negative and catalase positive. The growth conditions and bacteriocin activity were found optimum with MRS media at pH 7-10, Temp-35-40°C and salt tolerance at 1-3% which was optimized with MRS broth at pH 7.4, 37 °C, 1.5% NaCl for 48 h in shaking conditions @ 100 rpm. The isolate showed broad-spectrum antibacterial activity against gram positive (10-13 mm) and gram-negative (20mm) bacteria. It also strongly inhibited to fungus Aspergillus, Fusarium and Trichoderma. Bacteriocin from 60% ammonium sulphate fraction strongly inhibited to gram-negative R. planticola and Pseudomonas aeruginosa, which showed three protein bands of high molecular weight (nearly 40-70 kD) by SDS-PAGE analysis.