Continuous Hydrolysis of Olive Oil by Lipase in Microporous Hydrophobic Hollow Fiber Bioreactor

Abstract

Olive oil was hydrolyzed continuously at 40ºC by Candida cylindracea lipase in a small hollow fiber bioreactor (total area of hollow fibers was about 0.11 m²) in which the hollow fibers were made of microporous polypropylene. The lipase could be adsorbed easily onto oil-impregnated hollow fibers from its aqueous solution. The continuous feedings of olive oil inside the hollow fibers and of the buffer solution containing 18% glycerol as a stabilizer outside the hollow fibers were started after the enzyme-glycerol solution was removed from the bioreactor and the buffer-glycerol solution was added. An unvaried half life of 14 days of the adsorbed enzyme was observed when increasing amounts of the enzyme (1.0~5.0mg/ml) were put in, but its half-life was lowered to 6 days when the amount of the added enzyme was less (0.05mg/ml). Free enzymes in the enzyme solutions with and without 18% glycerol retained their initial activities equally for at least 3 months at temperatures below 4ºC. This suggests the feasibility of reuse of the enzyme-glycerol solution that was used in the preceding adsorption procedure after the solution was stored and supplemented with fresh enzyme. It was demonstrated by three successive cleanings and continuous hydrolyses that the used hollow fibers were regenerable. The productivity number was 0.81 mg-(unit)^-1 -h^-1, which was 26 times as great as that of the gel-entrapped lipase.