Production of medium‐chain glycerides by immobilized lipase in a solvent‐free system

Abstract Enzymatic synthesis of medium‐ chain glycerides (MCGs) was studied by using capric acid (decanoic acid) and glycerol as substrates for immobilized lipase (Lipozyme TM ) without any solvents or surfactants. Quantitative analysis of the reaction mixture was conducted by using highperformance liquid chromatography (HPLC), which enabled the exact tracing of the capric glyceride synthesis. Oleic acid was also used for comparison. The esterification activity of Lipozyme was determined at 40°C in an open batch reactor; the activities were 400 and 200 units/g for the capric glyceride and oleic glyceride synthesis, respectively. Maximum initial reaction rate was obtained at 50°C for capric and 60°C for oleic glyceride synthesis. The time course of the capric glyceride synthesis was compared in terms of different molar ratios, from which we infer that this enzyme is 1,3‐ specific, but not absolute, in this esterification reaction. The final conversion was greatly influenced by the methods used to remove water, among which the cold trap method resulted in a noticeable improvement.