Surface and Functional Properties of Biosurfactant Produced by Bacillus rugosus HH2 Derived from Jeotgal

Surfactants play a critical role in diverse industrial applications. However, concerns over the environmental persistence and toxicity of synthetic variants have prompted a shift toward sustainable biosurfactants. In this study, the surface properties of a biosurfactant produced by Bacillus rugosus HH2 isolated from Jeotgal, a traditional Korean fermented seafood, were investigated to evaluate its industrial applicability. The biosurfactant exhibited consistent and stable emulsifying performance across a wide range of salinity (3-18%), temperature (30-80°C), and pH (4-10) conditions. Emulsification assays with various hydrocarbon substrates revealed a performance equal to or better than that of the synthetic surfactant Triton X-100. While the biosurfactant generated a lower initial foam volume than Triton X-100, it maintained a significantly higher foam stability over 60 min, highlighting its suitability for applications that benefit from persistent and low-volume foaming. Optical microscopy showed that the biosurfactant produced smaller and more uniform bubbles than those of Triton X-100. Furthermore, the producing strain demonstrated strong hydrophobic interactions with hydrocarbons, such as hexadecane, toluene, and pyrene, supporting its potential utility in hydrocarbon-rich environments. Collectively, these findings highlight the multifunctional surface and functional activity and environmental robustness of the B. rugosus HH2-derived biosurfactant, indicating its potential as a sustainable and effective alternative for diverse industrial applications, including food processing, cosmetics, and environmental remediation.