Synthesis of medium-chain glycerides by lipase in organic solvent

Using commercial lipases from various microbial origins, medium-chain glycerides, such as mono-, di-, and tricaprin, were synthesized in isooctane from glycerol and capric acid. The enzyme reaction was performed with 0.35 M capric acid, 0.025 M glycerol, and 0.46 g silica gel to remove water in 5 mL of isooctane with 30 mg lyophilized lipase. Of the 21 kinds of lipases, 11 showed good synthetic activities. Lipases from Pseudomonas aeruginosa (Lipase PS), Rhizomucor miehei lipase and Chromobacterium viscosum lipase (Lipase CV) showed high activities for the production of tricaprin, while lipase OF-360 (from Candida rugosa) and lipase D (Rhizopus delemar) were good for dicaprin production. Lipases CC and MY from C. rugosa (C. cylindracea) also showed high activities for dicaprin and tricaprin. Some lipases, especially lipase PS, had high thermal stability over 60 degrees C. The optimal lyophilization pH to dehydrate the lipase coincides with the optimal buffer solution pH for hydrolysis.