Biosurfactant production potentials of microorganisms isolated from atmosphere of five petroleum stations at Tanke, Ilorin, Kwara State, Nigeria

Abstract

Biosurfactants aid in bioremediation by improving the bioavailability of hydrocarbon contaminants. The objective of this work was to isolate, enumerate and identify bacteria and fungi for their biosurfactant production potential in the atmosphere of five petroleum stations at Tanke, Ilorin, Kwara State, Nigeria using appropriate, standard microbiological methods (haemolysis test, emulsification index test, drop collapse test and oil displacement test). Fourteen bacteria and ten fungi were isolated in this study. The bacterial isolates belong to the genus Bacillus, Corynebacterium, Micrococcus, Staphylococcus, Listeria, Clostridium. The fungal isolates are of the genus Neurospora, Curvularia, Aspergillus, Fusarium, Rhizopus, Cladosporium, Colletotrichum, Sclerotinia. The mean number of bacteria counted during the sampling ranged from 3.48±1.15*10² CFU to 4.82 ±1.69*10² CFU, with petrol station 4 having the highest bacteria count (2.41*10² CFU) and petrol station 3 having the lowest bacteria count (1.74*10² CFU). The mean fungal count ranged from 7±3.7 CFU to 8.6±4.7 *10² CFU, with petrol station 4 having the highest fungal count (4.3 *10 CFU) and petrol station 3 having the lowest fungal count (3.4*10 CFU). Bacillus species showed promise of biosurfactant production after screening. Aspergillus fumigatus was the most prevalent fungus isolated (24%) while Staphylococcus epidermidis was the most prevalent bacterium isolated (11%). Some of these organisms are known opportunistic pathogens therefore, improved ventilation and sanitation of the petrol stations should be carried out to reduce the microbial load in the air. Also, bacteria that produce biosurfactant can be isolated from air of gas stations.