Production, Partial Purification and Characterization of Lipase Enzyme Expressed by Klebsiella pnemoniae of Vegetable Oil Contaminated Soil

Abstract

Lipases are a versatile class of enzymes owing to their ability to perform a specific range of biotransformations. Bacteria for lipase production were cultured on nutrient agar (NA) plates and identified using Gram Stain and biochemical tests. Screening for lipase producers was performed on NA media supplemented with 3% olive oil at 37 °C. Seven bacteria were isolated and identified as Bacillus megaterium, Klebsiella pneumoniae, Escherichia coli, Bacillus subtilis, Bacillus licheniformis and Micrococcus luteus. Lipase production was carried using standard methods and the best lipase producer was purified and characterized. The lipase enzyme from K. pneumoniae had a yield of 18.8% and was purified 26.3 fold. The optimum pH for the partially purified lipase was determined to be 8 with maximum activity at 30 °C. The lipase enzyme had affinity for substrates in the following order, olive oil > groundnut oil > palm oil and the activity of the enzyme was enhanced by metal ions in the following order, MgCl 2 > CaCl 2 > KCl whereas inhibitory effects were observed in the following order, CoCl 2 > HgCl 2 > CuSO 4 > FeCl 3. The lipase enzyme had V max of 0.0006 U/Sec, K m of 0.4960 mM and K cat of 0.0125 S-1 .