FACTORS INFLUENCING ESTER SYNTHESIS CATALYZED IN AQUEOUS-MEDIA BY THE LIPASE FROM CANDIDA DEFORMANS (ZACH) LANGERON AND GUERRA

The purified lipase from Candida deformans was shown to catalyse ester production in aqueous media by esterification of free fatty acids but not by alcoholysis. As the enzyme also catalysed ester hydrolysis, the influence of various physico-chemical factors on ester hydrolysis and synthesis was studied and compared. Substrate specificities were also studied. Both activities had the same pH and temperature optima, and did not require a metal cofactor. Tyrosine appeared to be one of the amino acids of the enzyme required by both catalytic activities, whereas serine-reactive reagents inhibited synthesis only. The highest synthesis and hydrolysis activities were obtained with mono-, di-and tri-unsaturated fatty acids containing a [cis] Delta-9 unsaturation and 16 to 18 carbon atoms. Only esters of primary alcohols were hydrolysed and synthesised. For alcohols ranging from methanol to butanol, synthesis activity increased with the length of the alcohol whereas hydrolysis activity of the corresponding esters decreased. The presence of alcohol inhibited hydrolysis. An optimum concentration was found for each primary alcohol at which ester synthesis was maximum and hydrolysis was low.