Isolation and molecular characterization of a newly isolated strain of Bacillus sp. HMB8,with a distinct antagonistic potential against Listeria monocytogenes and some other food spoilage pathogens

Antagonistic bacillus sp. strain hmb8 and its concomitant micrococcus sp. strain hmb7 were isolated from a healthy oral cavity of a volunteer. phenotypic characteristics and 16s rrna gene sequencing similarity confirmed that strain hmb8 belongs to bacillus genus,whereas strain hmb7 belongs to micrococcus genus. isolated bacillus sp. hmb8 exhibited considerable in vitro antagonistic activity against a broad range of indicator strains,including food spoilage bacteria,such as listeria monocytogenes,staphylococcus aureus,salmonella enterica salmonella enterica serovar typhimurium,pseudomonas aeruginosa,and escherichia coli. partial characterization of the bioactive compounds from the culture supernatant of the bacillus sp. hmb8 was carried out using three extraction methods; ammonium sulfate,chloroform-methanol,and ethyl-acetate. all extracts retained good antibacterial activity against all indicator strains,but to varying levels. overall,the ethyl-acetate extract of bacillus sp. hmb8 demonstrated the highest inhibitory activity against most indicator strains,notably against l. monocytogenes. the findings of the present study suggest that bacillus sp. hmb8 bioactive compounds may have potential biotechnological applications as food biopreservatives. © 2017 jordan journal of biological sciences.