Screening for Biosurfactant-Producing Bacteria Isolated from Abattoir Soil

Biosurfactants possess essential properties that make them highly indispensable in many industries, such as waste management, food, agriculture, and pharmaceuticals, due to their surface-active and wetting abilities. The search for microorganisms capable of producing this extensively utilized biomolecule is increasing daily. In this study, abattoir soil collected from Awka metropolis, Anambra State, was screened for biosurfactant-producing bacteria using mineral salt medium (MSM) supplemented with engine oil. Three bacterial isolates (NJ1, NJ2, and NJ3) were obtained from MSM agar. These isolates were subjected to four biosurfactant screening assays: haemolysis test, drop collapse test, oil spreading test, and emulsification index (E24). The results indicated that all three isolates showed alpha-haemolytic activity, and drop collapse positive reactions. Notably, NJ3 exhibited complete collapse reaction (+++) in the drop collapse test. Additionally, in the oil spreading test, NJ3 demonstrated the highest displacement of engine oil (10 mm), followed by NJ2 (7 mm) and NJ1 (5 mm). The determination of E24 using kerosene for all isolates revealed that NJ1 exhibited the highest E24 at 13%, while NJ2 and NJ3 had E24 of 2.56% and 2.50%, respectively. Morphological characterization, Gram’s staining, and biochemical analyses performed on the isolates, identified NJ1 and NJ3 as members of Streptomyces spp., while NJ2 was identified as Bacillus sp. These findings suggest that abattoir soil could be a potential source of biosurfactant-producing bacteria. Biosurfactants possess essential properties that make them highly indispensable in many industries, such as waste management, food, agriculture, and pharmaceuticals, due to their surface-active and wetting abilities. The search for microorganisms capable of producing this extensively utilised biomolecule is increasing daily. In this study, abattoir soil collected from Awka metropolis, Anambra State, was screened for biosurfactant-producing bacteria using mineral salt medium (MSM) supplemented with engine oil. Three bacterial isolates (NJ1, NJ2, and NJ3) were obtained from MSM agar. These isolates were subjected to four biosurfactant screening assays: haemolysis test, drop collapse test, oil spreading test, and emulsification index (E24). The results indicated that all three isolates showed alpha-haemolytic activity and drop collapse positive reactions. Notably, NJ3 exhibited a complete collapse reaction (+++) in the drop collapse test. Additionally, in the oil spreading test, NJ3 demonstrated the highest displacement of engine oil (10 mm), followed by NJ2 (7 mm) and NJ1 (5 mm). The determination of E24 using kerosene for all isolates revealed that NJ1 exhibited the highest E24 at 13%, while NJ2 and NJ3 had E24 of 2.56% and 2.50%, respectively. Morphological characterisation, Gram staining, and biochemical analyses performed on the isolates identified NJ1 and NJ3 as members of Streptomyces spp., while NJ2 was identified as Bacillus sp. These findings suggest that abattoir soil could be a potential source of biosurfactant-producing bacteria. Keywords: Biosurfactant, Abattoir, Oil Spreading, Screening, Streptomyces spp