IMPROVEMENT OF ALCOHOLIC FERMENTATIONS BY SIMULTANEOUS EXTRACTION ANDENZYMATIC ESTERIFICATION OF ETHANOL

An extractive biocatalysis process consisting of a biphasic aqueous-or ganic system was studied for the enzymatic esterification of ethanol, Oleic acid was used simultaneously as organic extractant and substrate for the esterification reaction which was catalysed by a free and imm obilized lipase from Rhizomucor miehei. The immobilization method used was the adsorption in a polyamide support-Accurel EP 700 [A.C. Olivei ra, M.F. Rosa, J.M.S. Cabral, M.R. Aires-Barros, Bioprocess Eng. 16 (6 ) (1997) 349-353.]. Some relevant parameters for the lipase catalytic activity such as ethanol concentration, oleic acid concentration and p H were studied using a 2((3)) factorial design expanded further to a c omposite design (CCD) [G.E.P. Box, W.G. Hunter, J.S. Hunter, Statistic s for Experiments, Wiley, New York, 1985; T.B. Barker, Quality by Expe rimental Design, Marcel Dekker, New York, 1985]. The response surface methodology was applied to the results. This biochemical process could be applied to the extraction of ethanol from fermentation broths of h igh glucose concentration [A.C. Oliveira, M.F. Rosa, J.M.S. Cabral, M. R. Aires-Barros, Bioprocess Eng. 16(6)(1997) 349-353]. In this work, t he performance of extractive fermentations of 300 g/l of glucose using a flocculent Saccharomyces cerevisiae sake strain and a non-flocculen t Saccharomyces cerevisiae strain were compared. (C) 1998 Elsevier Sci ence B.V. All rights resented.