Isolation of a broad spectrum antimicrobial producing thermophilic Bacillus and characterization of its antimicrobial protein.

Abstract

The hot spring water of Atri in India was believed to have disease curing property. An antibacterial producing organism was isolated and identified as Bacillus paralicheniformis by morphology, microscopy, and 16S-rRNA. Its secretion inhibited bacteria, yeast, and fungus in well-diffusion-method. The secreted antimicrobial was a 16.74kDa protein homologous of chicken-lysozyme-C. The novel lysozyme's activities were recorded under different parameters. It was active from pH 5-9 and endured up to 60°C for 120min. Complete cell wall lysis of S. flexneri and P. aeruginosa was observed under a microscope at 4500× with a minimum inhibitory concentration of 7.8µg/ml, while others required a higher dose, i.e., 13µg/ml, and 20µg/ml for E.coli and S. typhimurium, respectively. The discovered lysozyme has the extraordinary potential to lyse Gram-positive bacteria, yeast, fungus, and more efficiently lyse chick-lysozyme-C resistant lipopolysaccharide rich Gram-negative bacteria's outer cell wall.