Abstract
The optimal hydrolytic conditions for the hydrolysis of castor oil using the lipase from Pseudomonas sp. f-B-24 (lipase PC) were identified. The optimal amount of lipase for hydrolysis was found to be about 45μg per g of substrate. The optimal temperature was 40°C. The apparent Km and Vmax for castor oil hydrolysis were 416 g·l-1 and 110 μmol·mg-1·min-1, respectively. The addition of isooctane, Triton X-100, or PEG-6000 to the reaction mixture slightly improved the hydrolysis of castor oil using the enzyme, but CaCl2 inhibited it. The hydrolysis catalyzed by lipase PC was 1, 3-specific by TLC analysis of the enzymatic hydrolyzates of triolein, however the estolide, the intermolecular ester compound of liberated ricinoleic acid, was produced in the hydrolyzates of castor oil using lipase PC. Results of the hydrolyzability of lipase PC toward castor oil derivatives and the several methyl esters of C18-fatty acid showed that the hydrolytic activity of lipase PC was not affected either by hydroxyl groups of substituent or hydrophobic groups such as the O-acetyl group, though other lipases were affected by both.
