Screening and Optimization of Process Parameters for the Production of Lipase in Submerged Fermentation by Aspergillus carbonarius (Bainer) IMI 366159

Abstract

Aims: Lipases (triacylglycerol acylhydrolase EC 3.1.1.3) are enzymes that catalyze the hydrolysis of triacylglycerol at the oil-water interface to release glycerol and free fatty acids. In this study culture conditions and nutrient source modification studies were carried out on lipase production by Aspergillius carbonarius. Study Design: The work was based on a completely randomized design for the process parameters. All the experiments were conducted at least twice and the analyses were carried out in triplicates and average values were calculated for mean comparison. Methodology: The fungus was initially screened for the production of lipase using Rhodamine B agar media. Lipase production studies were conducted in a basal medium. Thereafter, the influence of carbon, nitrogen, pH, temperature and metal ions were examined on both the growth of fungus and its lipase production by monitoring the rate of olive oil hydrolysis by titration. Place and Duration of Study: The present study was conducted at the Food and Industrial Microbiology laboratory, Department of Microbiology, University of Port Harcourt, Nigeria between February 2012- October 2013. Results: Lipase production was detected as an orange halo around the fungal colonies under UV light at 350nm.The evaluation of suitable carbon and nitrogen sources for lipase production revealed that glucose (2%) and peptone (2%) yielded high lipase production. Olive oil (1.5%) was the best triglyceride (inducer) while the most suitable trace element for maximum lipase production was zinc sulphate (0.05%) followed by magnesium sulphate and manganese sulphate. Under optimal culture conditions, maximum lipase production (1.3 U/ml) was obtained in 96 h at 30ºC and pH 6.0 using 2% glucose as carbon source and 2% peptone as nitrogen. The correlation analysis carried out on all the experiment proved the interdependent of the physicochemical parameters and lipase production in A. carbonarius. Conclusion: The result obtained in this study indicated that A. carbonarius is a good producer of extracellular lipase; thus, making the fungus attractive for potential biotechnological applications.