Promising biosurfactant derived from Bacillus velezensis DG5714: A sustainable alternative to synthetic surfactants

Surfactants are indispensable in various industrial sectors; however, the poor biodegradability and environmental toxicity of synthetic surfactants have intensified the demand for sustainable alternatives. In this study, Bacillus velezensis DG5714 was isolated from an oil sludge-contaminated environment and comprehensively characterized in terms of its metabolic and genetic properties to validate its ecological safety and potential application as a biosurfactant-producing strain. The biosurfactant extracted from this strain was structurally identified as surfactin C. It exhibited exceptional surface activity, reducing the surface tension of water to 23.13 mN/m at a critical micelle concentration of 0.1 mg/mL. In addition, the biosurfactant demonstrated remarkable stability across wide ranges of pH (4-10), temperature (30-80 °C), and salinity (3 %-18 %). Functional assessments revealed that its foaming and emulsifying abilities were comparable to those of conventional synthetic surfactants. Toxicity evaluations, including hemolysis assays, in vitro cytotoxicity tests, and in vivo phytotoxicity assays, confirmed its excellent biocompatibility and ecological safety. Overall, the biosurfactant derived from B. velezensis DG5714 exhibits strong potential as a sustainable and effective alternative to synthetic surfactants owing to its excellent surface activity. In addition, this study presents a systematic approach for proposing sustainable alternatives to conventional synthetic surfactants.