Isolation and screening of biosurfactant producing strains of Bacillus spp. from soils on selected sites in North Macedonia

Abstract

Biosurfactants are eco-friendly, biodegradable, and versatile compounds with extensive industrial applications, notably in environmental bioremediation. Biosurfactants are known for lowering surface and interfacial tension within aqueous and hydrocarbon mixtures. Their primary application lies in the oil industry, where they enhance oil quality and assist in extraction processes, making oil recovery more efficient. Despite their diverse uses, the environmental distribution of biosurfactant-producing bacteria remains largely unexplored. This research focused on exploring the presence of biosurfactant-producing bacteria in both uncontaminated and polluted settings. Soil samples, totaling eight from polluted areas and four from undisturbed sites, were cultured on nutrient agar, and bacterial isolates were subsequently analyzed for their distinctive macroscopic and microscopic features, especially highlighting those with biosurfactant potential. Confirmation was carried out by Gram staining method of all isolates. Additionally, geochemical parameters of the soil samples were measured to emphasize the relevance of these strains for industrial applications and underscore their ecological role within soil environments. The biosurfactant potential of the 37 bacterial isolates was assessed utilizing the oil spread technique and hemolysis assay. Twenty of the isolates exhibited biosurfactant activity, primarily representing samples from contaminated soil environments. Bacterial isolates demonstrating significant biosurfactant production capabilities can be utilized for the bioremediation of contaminated soils. This application harnesses their natural properties to enhance the degradation of pollutants in affected environments.