Free lipase from Candida rugosa was used for the synthesis of butyl butyrate by direct esterification of butyric acid and butyl alcohol. A full factorial experimental design (2(4)) was employed to determine the effect of alcohol to acid ratio (1: 0.5-2.5), water adsorbent concentration (0-20%), enzyme concentration (40-80 mg) and incubation temperature (30-60 °C) on the esterification yield. Water adsorbent concentration has been found to be the most significant factor on the esterification reaction and its influence was negative. The extent of esterification was higher for substrates containing acid in excess even with a low enzyme concentration of 40 mg and 50% conversion was observed. The maximum predicted values for butyl butyrate yield (92.67%) can be attained with substrate containing acid in excess (molar ratio alcohol to acid 1:2.5), 80 mg enzyme concentration in the absence of water adsorbent at temperature incubation of 30 °C.
Lipase; Candida rugosa; Esterification; Experimental design
