Antagonistic behaviour of organic compounds from Bacillus species and Brevundimonas specie

Abstract

Bacterial strains, Bacillus cereus Lb (KF011486), Brevundimonas sp. A2 (JX996070), Bacillus cereus AZS and Bacillus sp. 11A, isolated from soil sample, were checked for their antimicrobial property against Bacillus as test organism. The bactericidal effect of the antagonistic strains against test organism was found to be at 1280, 1280, 40 and 160 arbitrary units (AU/ml), respectively. The Crude Antimicrobial Compound (CAC) had a bactericidal effect on target cell by degeneration of its cell wall. The chemical analysis of TLC purified extract of intracellular and extracellular antimicrobial compound produced by Bacillus cereus Lb by GC-MS analysis revealed the presence of organic compounds such as acetic acid and certain volatile organic substances such as, toluene, 2-butanone, etc., with antimicrobial property. N-acetylmuramoyl-L-alanine amidase is a cell wall hydrolysing enzyme and involved in cell wall degeneration of the target cells. These volatile organic compounds help this enzyme by decreasing the pH of the environment hence maximizing the amidase activity which possesses maximum activity at pH range of 5.5-6.5.