Farah Aisyah Nafidiastri, Salamun, Ninik Fadhillah, Ni'matuzahroh, Fatimah, Almando Geraldi, Amalia Rizky Febriyanti
Bacillus sp. are a group of bacteria that produce biosurfactants on agroindustrial substrates. This study aimed to determine the species name of Bacillus sp. ES7.3 and biosurfactant-related genes. Additionally, the growth response of Bacillus sp. ES7.3 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. ES7.3 was tested. The research included 16S rRNA gene detection, biosurfactant activity screening, biosurfactant biosynthesis gene detection, crude biosurfactant extract production from coconut meal, synthetic mineral water + 2% glucose media for comparison, and antifungal activity testing. The results of species identification showed that Bacillus sp. ES7.3 isolate was 99.31% homologous with Bacillus velezensis strain CBMB205. In turn, the biosurfactant activity of B. velezensis ES7.3 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 ES7.3 grown on coconut meal media produced a biomass of 2.9 mg/mL after 48 h of incubation. The production of crude biosurfactant by B. velezensis ES7.3 grown on coconut meal media was more effective than that of the 2% glucose Synthetic Mineral Water media substrate, as indicated by a greater percentage of emulsification activity and a lower surface tension on coconut meal media. Regarding the antifungal activity, B. velezensis ES7.3 was able to suppress the growth of Fusarium oxysporum by more than 50%. © 2026 by SPC (Sami Publishing Company), Asian Journal of Green Chemistry.
Doctoral Program of Mathematics and Natural Sciences, Faculty of Science and Technology, Universitas Airlangga, Surabaya, 60115, Indonesia; Department of Biology, Faculty of Mathematics and Natural Sciences, Universitas Negeri Surabaya, Ketintang, Surabaya, 60231, Indonesia; Department of Biology, Faculty of Science and Technology, Universitas Airlangga, Surabaya, 60115, Indonesia; Research Group of Applied Microbiology and Bioresource Technology, Universitas Airlangga, Surabaya, 60115, Indonesia; University of Co-E-Research Center for Bio-Molecule Engineering, Universitas Airlangga, Surabaya, 60115, Indonesia; Institute of Tropical Diseases, Universitas Airlangga, Surabaya, 60115, Indonesia; Faculty of Science and Technology, Sunan Ampel Islamic University, Surabaya, Indonesia
