Identification and Screening of Biosurfactant Producing Bacteria from Mechanic Workshops Soil in Gusau Metropolis, Nigeria

Abstract

Biosurfactants are molecules that reduce interfacial tension. Their chemical composition can vary widely, but they have in common their amphiphilic or amphipatic nature and can thus be soluble in aqueous as well as in organic solvents. The study was carried out to identify and screen biosurfactant producing bacteria from mechanic workshops in Gusau metropolis. Eight (8) soil samples were collected at the depth of 0-7 and 8-15cm from selected mechanic workshops located at Gada Biyu, Taqama bye-pass, Birnin Ruwa and non-oil contaminated soil as control for analysis. The physicochemical parameters were analysed using standard procedures (blood heamolysis, drop collapse, oil displacement and emulsification index) methods were used to screen biosurfactant production by the isolates. Mineral salt medium supplemented with 1% Actual gasoline oil (AGO) as sole sources of carbon was used to isolate hydrocarbon degrading bacteria, while heterotrophic bacteria were isolated using nutrient Agar. The soil samples from the study area were characterised with smooth, grey to dark brown soil with an unpleasant smell as well as as well as high temperature and pH. The three mechanic workshops used for this study, shows relatively higher counts for Hydrocarbon Degrading Bacteria while higher heterotrophic bacterial count was obtained from the control site though there was no significant difference between individual mechanic workshop (p>0.05). The isolates are potential biosurfactant producers based on their performance especially blood haemolysis and emulsification index. The isolates identified belonged to the species of Bacillus, Pseudomonas, Acinetobacter, Micrococcus and Serratia.