Titration vs. GC-MS Analysis to Determine the Factors Affecting the Esterification Activity of Candida rugosa Lipase Immobilized onto Celite

¹ Chemical Engineering Department, Faculty of Engineering, Universitas Indonesia, Depok 16424, Indonesia
² Chemical Engineering Department, Faculty of Industrial Technology, Universitas Pertamina, Jakarta, 12220, Indonesia
³ Bioprocess Engineering Program, Department of Chemical Engineering, Faculty of Engineering, Universitas Indonesia, Depok 16424, Indonesia
⁴ Chemical Engineering Department, Faculty of Engineering, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia
⁵ Research Center for Biomass Valorization, Faculty of Engineering, Universitas Indonesia, Depok 16424, Indonesia

^* Corresponding author: mgozan@ui.ac.id

Abstract

The activity of lipases to catalyze the synthesis of esters in a non-aqueous environment can be assessed by performing a simple esterification study. In such tests, titration of the remaining acid has been one of the most used methods to determine the reaction progress due to its simplicity. Nonetheless, the execution of the titration is not always as simple as it sounds. In this study, Candida rugosa lipase is immobilized onto celite matrix, and its esterification activity was evaluated by catalyzing the reaction between butanol and butyric acid. Among the factors affecting the esterification activity of the immobilized enzymes are celite:CRL ratio, buffer pH during immobilization, and post-immobilization drying time. The titration results were analyzed using factorial design, ANOVA test, and Pareto chart. Here, the ambiguity of the titration results is showcased. On the other hand, analyzing the esterification results using GC-MS allowed optimization of the immobilization method to be performed. Finally, factors affecting the activity of the immobilized enzyme can be better assessed when the esterification results were analyzed using GC-MS.