Isolation and characterization of lipolytic bacteria from oil mill effluent in Nassarawa Local Government Area, Kano State.

Abstract

Oil mill effluent is a significant source of environmental pollution containing high concentration of fats and oil posing problems including blocking drainages, oxygen depletion, increasing soil acidity e.t.c. These lipolytic bacteria (Lipase producing bacteria) play a pivotal role in environmental remediation thereby breaking down complex lipid into fatty acids and glycerol. This study aimed to isolate and characterize lipolytic bacteria from oil mill effluent, nutrient agar was used to isolate bacteria from oil mill effluent by pour plate method. Bacterial isolates were screened for their ability to produce lipase using egg yolk and oil displacement test to determine primary activity of lipase. Quantification of lipase activity was carried out by standard titrimetric method. Morphological and biochemical characterization of the screened isolates revealed that they are members of the Bacillus species according to Bergey’s Manual. Ten (10) bacterial isolates were obtained, six were positive for both tests.  Eight were further screened to quantify enzyme activity with the inclusion of E1 and E2 which displayed very good oil displacement. The highest enzyme activity was obtained from E9 (0.176U/ml) and the least enzyme activity from E7 (0.041U/ml). Distinct bacterial isolates identified as Bacillus cereus, Bacillus licheniformis, Bacillus megaterium and Bacillus polymyxa have demonstrated significant lipolytic activity. These findings highlight oil mill effluent as a valuable source of lipolytic bacteria with application in general remediation of oil contaminant.