Selective hydrolysis of epoxidized soybean oil by commercially available lipases: Effects of epoxy group on the enzymatic hydrolysis

Eight lipases were studied in hydrolysis reactions toward the goal of selectively removing saturated fatty acids from epoxidized soybean oil. Commercially available epoxidized soybean oil has about 18% saturated fatty acids, which manifest themselves as branches when used in polymers. The removal of these fatty acids creates a potentially valuable degree of freedom in the processing of soybean oil for polymer applications.Hydrolysis was achieved with seven of the eight enzymes with the epoxy functionality increasing reaction rates and changing selectivities. Lipases from Penicillium roquefortii, Mucor javanicus, Rhizomucor miehei and Pseudomonas sp. showed selectivity toward diepoxy acyl moieties. Aspergillus niger lipase selectively hydrolyzed saturated fatty acids in soybean oil but the lipase was not selective with epoxidized soybean oil. Penicillium camembertii lipase was found to be an inactive enzyme for triglyceride substrates. The selectivity of Candida rugosa toward saturated fatty acids increased in epoxidized soybean oil. Burkholderia cepacia lipase had selectivity toward both palmitic acid and stearic acid but not the epoxy acyl moieties. A hypothesis is proposed that explains unexpected trends in the selectivities of the lipases.