BIOCHEMICAL ATTRIBUTES AND SCREENING OF POTENTIAL BIOSURFACTANT-PRODUCING SOIL ACTINOBACTERIA

Abstract

The current research aims to examine the biosurfactant-producing ability of microbial isolates by emulsification activity and hydrocarbon adhesion. Microbial isolates were cultivated in acceptable culture medium, and cell free supernatants were utilised to measure emulsification index (E24) using three hydrocarbons: hexane, petroleum oil, and crude oil. The bacterial adhesion to hydrocarbons (BATH) experiment was conducted to measure cell surface hydrophobicity and the capacity of cells to attach to various hydrocarbons. Emulsification tests indicated that only 10% of the isolates exhibited negative emulsification activity, while approximately 50% displayed significant emulsification indices with all three hydrocarbons. Petroleum oil generated the highest average E24 values, suggesting higher substrate compatibility for biosurfactant detection. Stable emulsification was also reported with hexane and crude oil for numerous isolates. The BATH test demonstrated that most isolates displayed highest adhesion toward hexane (92.23 ± 0.51 to 52.15 ± 1.42%) demonstrating a high level of hydrophobicity and implying robust biosurfactant-mediated cell–hydrocarbon interaction. Together, our data demonstrate that a majority of the isolates exhibit high emulsifying activity and hydrocarbon-binding potential (73.00 ± 0.1 to 4.00 ± 0.1%). The combined examination of emulsification index and hydrocarbon adhesion reveals that most isolates contain high biosurfactant-producing potential (95.25 ± 0.02 to 18.00 ± 0.02%). These results emphasise their potential for use in bioremediation, hydrocarbon degradation, and other industrial processes requiring effective natural surfactants.