Optimization, Purification and Characterization of Lipase by Pseudomonas aeruginosa Isolated from Palm Oil Processing Cottage Industries in Ekiti State, Nigeria

Abstract

Introduction: The importance of palm oil in the country is due to the versatility of applications of their by-products, such as cooking oil, margarines, soaps, detergents, cosmetics, lubricants, biofuels and electric power, among many others. Aims: This study investigates the optimization, purification and characterization of lipase produced by Pseudomonas aeruginosa isolated from palm oil processing cottage industries. Methodology: Effluent samples were taken from a depth of 10 – 15 cm in six different locations within Ekiti State, Nigeria. Bacteria species isolated from the effluents and identified using standard microbiological techniques and molecular characterization. The physiochemical characterizations of the isolates were carried out and the process parameters (nitrogen, carbon, temperature and pH) were optimized. Partial purification of crude extract from P. aeruginosa was carried out by ammonium sulphate precipitation and dialysis. Results: The pH of the inoculum ranged from 6.23 to 6.01 oil and grease contents ranged from 149.6 to 114.2 mg/l while the biochemical oxygen demand ranging from 42760 to 33800 mg/L. The chemical oxygen demand ranged from 1.9 to 1.8 mg/L. Pseudomonas aeruginosa exhibited considerable enzyme activity ranging from 75.33 to 22.44 µmol/min/mL. High lipase activity of 2.68 µmol/min from P. aeruginosa was recorded from a medium supplemented with palm oil, while the medium supplemented with goya oil had least lipase activity 2.31 µmol/min. The lipase activity increased with increase in incubation temperature at 50°C with relative activity of 99.9 % before it declined to 15 % at 80°C. Conclusion: The lipase produced from the P. aeruginosa exhibited high lypolytic activities. It can therefore, be a biodegradable agent for industrial applications especially in the waste treatment especially of waste rich in oil and fats. Thus, lipase may act as a biodegradable agent for industrial applications.