In-vitro antibacterial, antifungal, antioxidant and functional properties of Bacillus amyloliquefaciens

BACKGROUND: Food born pathogenic bacteria and filamentous fungi are able to grow on most foods, including natural foods, processed foods, and fermented foods and create considerable economic loss. The aim of this study was to determine the antibacterial, antifungal, antioxidant and functional properties of Bacillus amyloliquefaciens recovered from silage. METHODS: Minimum Inhibitory Concentration (MIC) of the compounds was assessed by using broth micro dilution method. The 1,1-diphenyl-2-picrylhydrazyl (DPPH)-radical scavenging and hydroxyl radical-scavenging abilities were measured to evaluate antioxidant activity of the strain. RESULTS: Primary antimicrobial compound production screening revealed that B. amyloliquefaciens exhibited significant activity against all the tested bacteria and fungi compared to other strains. The 16S rRNA and gyrase A gene sequence analysis determined using molecular biological tools confirmed that the strain was 99% similarity towards B. amyloliquefaciens. The Minimum Inhibitory Concentration (MIC) of ethyl acetate extract against Bacillus subtilis, Enterococcus cloacae and Staphylococcus aureus were 25.0 μg ml-1, and S, epidermidis were 12.5 μg ml-1, respectively. Filamentous fungi Aspergillus clavatus, A. fumigates, A. niger and Gibberella moniliformis showed 25 μg ml-1. VJ-1 was able to survive the gastrointestinal conditions simulating the stomach and duodenum passage with the highest percentage of hydrophobicity. In addition, its resistance to hydrogen peroxide and highest hydroxyl radical and 2, 2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activities, with inhibition rates of 56.84% and 67.12% respectively, were its advantage. An antimicrobial susceptibility pattern was an intrinsic feature of this strain, and thus, consumption does not represent a health risk to humans. CONCLUSION: Bacillus amyloliquefaciens might be a promising candidate for new pharmaceutical agents and probiotics.