Title : Fatty acid methyl ester analysis of olive oil degraded by Pseudomonas fluorescens and enzymatic characterisation of the lipase
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. Fatty acids are the major components of lipids; and the physical, chemical and physiological properties of a lipid class depend primarily on its fatty acid composition. 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 and to check the fatty acid composition of olive oil. Gas chromatography method can be used for the identification of microbiological degraded fatty acids in vegetable oils as methyl ester.
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. Olive oil degraded by lipase of Pseudomonas fluorescens grown in two different Mineral Salt Medium, was studied over 25 days. Olive oil was analyzed for fatty acids commonly present in olive oils which are Myristic, Palmitic, Stearic, Oleic, Linoleic, Linolenic, Behenic and Lignoceric, which have specific carbon number and their values in approximate percentage are C14:0 (0.4), C16:0 (14.0), C18:0 (5.5), C18:1 (76.4), C18:2 (3.4), C18:3 (0.1), C22:0 (0.1) and C24:0 (0.1) respectively. Oleic acid percentage is high in olive oil which contained considerable amount of 76.4%.
The reduction of fatty acid by Pseudomonas fluorescens after 20 days was 8.2% in the media used. Lipase from Pseudomonas fluorescens had potential for degradation of fatty waste. It could therefore be employed in environmental cleanup of oil spill site.