Multiple effects of water content on solvent-free enzymatic esterifications

FORESTI, MARÍA LAURA; PEDERNERA, MARISA; BUCALÁ, VERÓNICA; FERREIRA, MARÍA LUJÁN

Buenos Aires, Argentina.

Congreso; XXII Congreso Interamericano de Ing. Qca. y V Congreso Argentino de Ingeniería Química; 2006

Confederación Interamericana de Ingenieros Químicos

 Enhancement of the catalytic activity of lipases has commonly been performed by biocatalyst modification. In this work, the enhancement of the reaction rates obtained in lipase-catalyzed esterifications is achieved through modification of the characteristics of the medium in which reaction takes place. In particular, this work is focused on the effect that the water present in the reaction medium has on lipase-catalyzed esterifications. Considering both, the need of biocatalyst hydration and the prevention of the hydrolysis of the ester produced, literature on lipase-catalyzed esterifications agrees on the existence of optimum water contents in the range of 0.2-3%. However in the solvent-free enzymatic esterification of oleic acid with ethanol, the addition of relatively high amounts of water (much higher than 3%) drastically increased the esterification rate upon formation of a second aqueous phase. In this work we demonstrate that the existence of a second aqueous phase favors the reduction of the water content in the organic reactive phase, increasing the fatty acid conversion in the first hours of reaction. Experimental and modeling data are presented to illustrate the topic. Keywords: Lipases, Esterification, Two-liquid Phases System.