ESTERIFICATION AND TRANSESTERIFICATION CATALYZED BY CUTINASE IN REVERSE MICELLES OF CTAB FOR THE SYNTHESIS OF SHORT-CHAIN ESTERS

Reverse micelles formed using the cationic surfactant, hexadecyltrimet hylammoniumbromide (CTAB) were applied as a reaction medium for esteri fication and transesterification (alcoholysis) reactions catalysed by a recombinant lipolytic enzyme, cutinase. Reactions were initially stu died with either the alcohol substrate (acyl acceptor) or chloroform a s cosurfactant. Chloroform was inhibitory to the enzyme. The enzyme de monstrated specificity towards short chain substrates and these were u sed to study some relevant parameters affecting specific activity. Opt imum values for w(o), buffer concentration, pH, CTAB concentration and temperature were identified. Optimum value for w(o) was the same for the two reactions whereas the effects of buffer concentration, pH, CTA B concentration and temperature were different. An optimum level of al cohol was identified, this was the same for both reaction types but th e value was dependent on the alcohol. Fatty acids showed inhibitory ef fects at comparatively low concentrations compared to ester which show ed no inhibitory effects at much higher concentrations. Reducing the e nzyme concentration resulted in an increase of specific activity. Cuti nase showed good stability in CTAB reverse micelles with hexanol as co surfactant, (half Life > 100 days), whereas in the presence of chlorof orm a rapid loss of much of the activity was observed in the first few hours.