Isolation and characterization of lipase producing bacteria in hydrocarbon contaminated sites in Kano Metropolis

Abstract

Lipase (Triacylglycerol hydrolases EC 3.1.1.3) is an enzyme capable of hydrolyzing lipids into fatty acids and glycerol. It possesses numerous industrial applications such as pharmaceuticals, food, detergents, paper and pulp, agrochemicals, biosurfactants and bioremediation, etc. Many attempts have been made to isolate lipase producing microorganisms since this enzyme is used in many biotechnological processes. This study was aimed at isolation and characterization of lipase producing bacteria in hydrocarbon contaminated soil sites in Kano metropolis. Bacterial isolation was done through serial dilution technique; and screened on tributyrin agar plates for lipase production. A total number of 49 pure bacterial culture were isolated from hydrocarbon contaminated soil samples from the three different hydrocarbon contaminated soil sites; eighteen distinct isolates indicated lipase production after lipase screening. Lipolytic activity assay revealed no significant difference in the lipase hydrolysis capacity (HC) of the isolates. Furthermore, the lipolytic bacteria isolates were characterized by morphological and biochemical tests and identified by molecular tool through sequencing method. Three distinct selected isolates were morphologically characterized as gram-negative, rod and coccus cells and 16S rRNA sequence analysis revealed isolate A4 to have 94.91% similarly to the Pseudomonas spp. (Pseudomonas azotoformans strain LMG 21611), isolate B4 also exibited 87.99% similarity to the Pseudomonas genus (Pseudomonas fluorescens strain PF-7) while isolate C1 showed 97.57% similarity to Acinetobacter genus (Acinetobacter baumannii strain NWPRD). These bacterial strains can be used for the production of lipase enzyme for various industrial applications and bioremediation.