Kinetic study on esterification of ascorbyl oleate catalyzed by Lipase NS 88011

Abstract

In this study, bisubstrate kinetics mechanism models were correlated with the experimental data of ascorbyl oleate using the new lipase preparation, Candida antarctica NS 88011, and kinetic parameters (Vmax, Km, and Ki) were estimated. The highest conversion (49.42 %) was observed at 1 h of reaction using the ascorbic acid/oleic acid molar ratio of 1:9, 70 ºC and 30 % of enzymatic loading. The Ping Pong Bi-Bi model showed better congruence with the experimental data for all the effects evaluated. The kinetic constants showed that the lipase had an identical affinity, with a value of 0.81 for both substrates and inhibitory constant (Ki) of ascorbic acid (1.959) much higher than oleic acid (0.0008). It has been demonstrated that lipase has good operational stability (14th cycle). The results obtained with the new immobilized enzyme are valuable to elucidate the reaction mechanism. In addition, it represents an important contribution to optimize the reaction and create strategies to increase the productivity of the esters of vitamin C.