Enzymatic catalysis of vegetable oil with ethanol in the presence of co-solvents

Abstract

This article evaluates the production of biodiesel or FAEE (fatty acid ethyl esters) from vegetable oil by enzymatic catalysis with ethanol as reagent and in the presence of hexane as co-solvent. A three-factor design of experiments was performed to evaluate the influence of the following three variables on the reaction performance (or the ethyl esters content): reaction time (24, 36, and 48 h), co-solvent percentage (10, 20 and 30 %, v/v), and oil/alcohol molar ratio (1:4, 1:6, 1:8), at fixed reaction temperature (35 degrees C) and fixed mass of Lipozyme TL IM (enzyme/oil mass ratio of 1.6 wt%). Results show that the best operating conditions to perform the reaction are: oil/alcohol molar ratio of 1:4, 10 % (v/v) of hexane co-solvent, and 48 h of reaction time. Although most of the biodiesel quality parameters evaluated are out of the NP EN14214:2009 standard limits, for the above mentioned conditions it is possible to obtain a lower viscosity biodiesel, with lower density, lower CFPP (cold filter plugging point), and with a lower alkaline metals (Na+ and K+) content.