This study evaluated the inhibitory effects and adhesion properties of the isolated
Bacillus safensis strain VQV8 (abbreviated as VQV8) against pathogenic Vibrio species
under different culture conditions. VQV8 was cultured under specific conditions of
temperature, pH, and NaCl (%) before testing its antibacterial activities using the dotspotting method. In addition, a medium from agriculture by-products was screened for
replacing Marine broth (MB) medium to culture VQV8. The bacteriostatic activities of
VQV8 against pathogenic Vibrio bacteria were also determined. The adhesion properties
of this bacterium were evaluated based on three main attributes: hydrophobicity,
aggregation, and biofilm formation. The results indicated that VQV8 had the highest
antibacterial activities against the tested Vibrio species when cultured in a medium
containing 2% NaCl and incubation temperature ranged from 25 to 37 °C. However, the
antibacterial activities against V. parahaemolyticus, V. haveyi, and V. alginolyticus were
not found at 45 °C. Additionally, the pH from 6 to 9 did not demonstrate a significant
effect on the antibacterial activities of VQV8. On the other hand, the use of pineapple
peel extract (20–30%) medium demonstrated no significant difference in either growth or
antibacterial activities of VQV8 compared to those found in MB medium. These results
suggest the potential ability of this bacterial strain to strongly inhibit the growth of all
tested Vibrio spp. High adhesion ability was also confirmed through the results of the
hydrophobicity, aggregation, and biofilm formation assays. Thus, our results suggest that
VQV8 could be used as a potential probiotic candidate for the prevention of Vibrio spp.
infections in aquaculture.