Biosurfactant Production Using Coconut Meal by Indigenous Bacillus velezensis ES۷.۳: Genetic Characterization and Antifungal Activity against Fusarium oxysporum

Bacillus spp. are a group of bacteria that produce biosurfactants on agroindustrial substrates. This study aimed to determine the species name of Bacillus sp. ES۷.۳ and biosurfactant-related genes. Additionally, the growth response of Bacillus sp. ES۷.۳ on coconut meal media, the activity of the crude biosurfactant extract, and the effectiveness of crude biosurfactant extract production on coconut meal and glucose were compared. The antifungal activity of Bacillus sp. ES۷.۳ was tested. The research included ۱۶S rRNA gene detection, biosurfactant activity screening, biosurfactant biosynthesis gene detection, crude biosurfactant extract production from coconut meal, synthetic mineral water + ۲% glucose media for comparison, and antifungal activity testing. The results of species identification showed that Bacillus sp. ES۷.۳ isolate was ۹۹.۳۱% homologous with Bacillus velezensis strain CBMB۲۰۵. In turn, the biosurfactant activity of B. velezensis ES۷.۳ isolate was characterized by the formation of a clear zone around the colony on blood agar media. Furthermore, surfactin thioesterase biosynthesis genes srfAD and ituD were detected. Meanwhile, B. velezensis ES۷.۳ grown on coconut meal media produced a biomass of ۲.۹ mg/mL after ۴۸ h of incubation. The production of crude biosurfactant by B. velezensis ES۷.۳ grown on coconut meal media was more effective than that of the ۲% glucose Synthetic Mineral Water media substrate, as indicated by a greater percentage emulsification activity and a lower surface tension on coconut meal media. Regarding the antifungal activity, B. velezensis ES۷.۳ was able to suppress the growth of Fusarium oxysporum by more than ۵۰%.

کلیدواژه ها:

Bacillus velezensis ، Biosurfactant ، Lipopeptide ، Coconut meal ، Antifungal activity ، Fusarium oxysporum