Characterisation of a Bacterium Lipase (Bacillus subtilis) from Vegetable Oil Polluted Soil

Bacteria are very useful in protecting the environment. The lipolytic activities of physiologically diverse bacteria have great potential to degrade oil spills in the environment. There is need for extensive characterisation of the bacterium lipase for the treatment of vegetable oil-polluted sites. This work was carried out to preliminarily characterise the lipase of Pseudomonas fluoresens. Pseudomonas fluoresens was screened for lipase production using standard methods. Temperature, pH, ion concentration (NaNO3 and MgSO4), enzyme concentration, nitrogen concentration, substrate concentration, time course and agitation speed were optimised for the lipase activity as well as growth. Crude enzyme of Pseudomonas fluoresens had the highest lipase activity and growth of 0.8 U/mL and 1.418 mg/mL respectively at room temperature, but when production was optimised higher activity 0.9 U/mL was seen in the use of glucose as substrate. Agitation with the speed used did not support lipase production but supported growth (1.998 mg/mL) at agitation speed of 100 rpm. Different substrate concentration which had optimum enzyme activity for Pseudomonas fluoresens had activity of (1.1 U/mL), was at 1.0 %. At 30oC Pseudomonas fluoresens had activity of 1.0 u/mL. Substrate concentration had optimum growth (1.778 mg/mL) at 0.5 %. The enzyme has good potential for the hydrolysis of vegetable oils, which is an important factor in environmental cleanup of vegetable oil spill site.