CHARACTERIZATION OF BIOPESTICIDE COMPOUNDS FROM Bacillus subtilis AAF2 UAAC 20701 FERMENTATION PRODUCTS

Abstract

The characterization of biopesticide compounds from extract of fermentation products using Bacillus subtilis AAF2 UAAC 20701 has been investigated. The fermentation process was carried out in a 1 liter volume bioreactor using a modified corn immersion media with 110 rpm agitation, 370C temperature, initial pH of 7, for 48 hours. Supernatant from fermented products that have been separated from bacterial cells, then extracted and fractionated using organic solvents: hexane, dichloromethane and ethyl acetate. Each fraction was dried and tested for its antimicrobial activity against the Ralstonia solanacearum fungal test, Xanthomonas campestris, Fusarium oxysporum and Ssclerotium rolfsii. The separation of active substance compounds was performed by preparative Thin Layer Chromatography (TLC) and subsequently characterized using Ultra violet-Visible (UV-Vis), Spectroscopy, Fourier Transform Infra Red (FTIR) Spectroscopy, Liquid Chromatography-Mass Spectra (LC-MS). The results showed that the highest antibiotic activity was obtained from ethyl acetate extract with 100% resistance to both fungi isolates, followed by dichloromethane extract with 76.0% resistance to Fusarium oxysporum and 63.3% to Sclerotiumrolfsii, and the lowest activity was obtained in hexane extract with resistance of 72.0% to Fusarium oxysporum and 38.3% to Sclerotium rolfsii. The ethyl acetate extract has two compounds, with Rf of 0.78 (AAF21) and 0.59 (AAF22) respectively. The AAF22 compounds had high antibiotic activity against Fusarium oxysporum (92.0%) and Sclerotium rolfsii (91.7%), compared with AAF21 to Fusariumoxysporum (70.0%) and Sclerotiumrolfsii (55.0%). Both AAF21 and AAF22 is a potential compound to be developed as biopesticide. The AAF2² compound is allegedly to be L- Homocysteine (C8H16N2O4S2).