Natural flavour ester production by immobilized Candida cylindracea lipase in organic solvent


Gillies, Richard Bruce




Production of natural flavour esters by lipase was studied. Lipase can catalyze ester formation when an organic solvent, capable of extracting the ester, is used as a bulk phase solvent. Candida cylindracea lipase, which shows broad substrate specificity and pH stability, was immobilized by adsorption to silica gel. Synthesis of ethyl butyrate was studied as a model. The immobilized lipase was shaken in n-heptane containing ethanol and butyric acid. Ester production rate was optimal around: pH 4, decreasing at higher pH values; 30°C, decreasing at higher temperatures; substrate concentration of 0.4 M ethanol and 0.25 M butyric acid. Enzyme hydration was found necessary for stable activity in repeated use. A variety of flavour esters was produced. Ethyl butyrate production was also evaluated in a packed column of immobilized lipase through which a solution of hexane containing substrate was recycled. With a solution volume to packed bed ratio of 3:1, a space velocity of 20h-1 was found to maximize ethyl butyrate production.


Esters -- Synthesis




Carleton University

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Theses and Dissertations

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