Hydrolysis of soybean oil by surfactant-coated lipase in organic solvents

The advantages of coating surfactants onto the lipases for catalyzing lipol ytic reactions in organic solvents motivated this investigation. The fatty acids obtained from hydrolysis of soybean oil are of nutritional value and are beneficial to the cardiovascular system. A lipase from Candida rugosa w as used to prepare a surfactant-coated lipase (SCL) for catalyzing the hydr olysis of soybean oil. The conditions for obtaining a superior SCL, includi ng the kind of surfactant, weight ratio of surfactant / lipase and pH of th e buffer solution were investigated. These factors significantly affected t he catalytic power, yield of SCL, protein content and the coverage of lipas e by surfactant. The results obtained were explained by the hydrophile-lipo phile balance (HLB) of the surfactant and the log P (hydrophobicity) of the organic solvent. The optimum conditions for preparing SCL for enhancing th e hydrolysis of soybean oil were pH = 5.0 and weight: ratio of Span 60 and lipase = 4/1. The catalytic activity of the SCL was 3.6 fold greater than p owdered Lipase. The optimum conditions for hydrolysis were investigated by varying the organic solvent as well as the temperature and pH of the milieu . SCL exhibited the highest hydrolysis rate at 37 degreesC: in a buffer sol ution of pH7.0 with isooctane. A conversion rate of 96.28% was reached in 1 2.3 hr.