Introduction: Biosurfactants are made up of naturally occurring molecules such as lipopeptide, glycoprotein, lipoprotein, and fatty acids. Using biosurfactants rather than chemical and synthetic surfactants is safer. Objective: The aim of this study was to investigate biosurfactant properties and antibiotic resistance of soil bacteria, Bacillus salmalaya strain 139SI. Bacillus salmalaya produces biosurfactants, which capable of reducing surface tension of certain media, as they are surface-active molecules. Methods: In current study Parafilm M Test, Drop Collapse, Oil spreading methods for biosurfactants screening were used and antibiotic analysis was done using an aseptic technique. Results: 600μl biosurfactant (460 mg/ml) was the most effective volume to produce large diameter of oil spreading zone when 700 μl of oil was used. 0.23g freeze-dried supernatant powder mixed with 0.5 ml distilled water (460 mg/ml) produced larger clearing zone than powder mixed with 1 ml (230 mg/ml) and 1.5 ml distilled water (153 mg/ml). In cleaning activity of crude oil container, biosurfactant was able to clean oil in the container and this can be applied in cleaning oil waste from crude oil tank and can also be used to clean oil spillage. In antibiotic analysis study, ten soil bacteria isolates included Bacillus salmalaya were selected. Conclusion: All isolates had shown different sensitivity towards different antibiotics. Bacillus salmalaya showed sensitivity to almost all selected antibiotic compared to other isolates. This indicated that this strain is safe to be used as it was sensitive to many antibiotics.
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