Determination of Biologically Active Substances Responsible for Antimicrobial Activities of Bacillus Species with Gas Chromatography–Mass Spectrometry (GC-MS) Analysis
Ayegba S. O.
Egbe N. E.
Haroun A. A.
Olukotun G. B.
Abdallah H. Y.
Ajibade Y. H.
Egbi T.K.
Abstract
Soil-borne Bacillus spp. represents a prolific source of antimicrobial compounds, yet their full potential remains underexplored. In this research, twenty soil samples were obtained from four different sites in Gwagwalada, FCT, and subjected to serial dilution before plating to isolate presumptive Bacillus species. Eight Gram-positive, catalase-positive, endospore-forming strains were purified, biochemically characterized, and identified by 16S rRNA sequencing as B. licheniformis, B. pumilus, B. amyloliquefaciens, two B. circulans strains, B. cereus, B. brevis, and B. subtilis. Gas Chromatography/Mass Spectrometry (GC–MS) profiling of the five top extracts revealed 110 volatile and semi-volatile compounds, dominated by acetoin (up to 80 mg/L), 2,3-butanedione, and branched-chain fatty acids, which support the observed bioactivities. These findings validate Gwagwalada soils as reservoirs of potent antimicrobial Bacillus strains, establishing practical guidelines for media formulation, targeted strain selection, and metabolite purification for scaling up the production of natural antibiotics for agricultural and clinical applications.
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