Immobilization of lipase on sepabeads and its application in pentyl octanoate synthesis in a low aqueous system

Abstract

The object of the study was to investigate the process conditions relevant for the pentyl octanoate production with the lipase from Candida rugosa immobilized on Sepabeads EC-EP carrier. This is an epoxide-containing commercial polymethacrylic carrier with suitable characteristics for enzyme immobilization. The immobilized lipase suitable for pentyl octanoate synthesis has been prepared by a direct lipase binding to polymers via their epoxide groups. The enzymatic activity was determined by both hydrolysis of olive oil in an aqueous system and esterification of n-pentanol with octanoic acid in a low aqueous system. The influence of several important reaction parameters such as temperature, initial water content, initial substrate molar ratio, enzyme loading and time of adding of molecular sieves in the system is carefully analyzed by means of an experimental design. Production of the ester was optimized and an ester production response equation was obtained, making it possible to predict ester yields from known values of the five main factors. Almost complete conversion ( gt 99%) of the substrate to ester could be realized, using lipase loading as low as 37 mg/g dry support and in a relatively short time (24 h) at 45ºC, when high initial substrate molar ratio of 2.2 is used.

U radu su ispitani uticaji procesnih parametara na sintezu pentil-oktanoata pomoću lipaze iz Candida rugosa imobilisane na komercijalni polimetakrilatni nosač (Sepabeads EC-EP). U radu je primenjena metoda imobilizacije enzima koja se zasniva na direktnom vezivanju enzima za nosač preko epoksidne grupe polimera. Aktivnost imobilisanog enzima ispitana je u vodenom sistemu na model reakciji hidrolize maslinovog ulja kao i u nevodenom sistemu na modelu sinteze pentil-oktanoata u izooktanu. Ispitani su uticaji pet procesnih faktora na enzimsku sintezu datog estra primenom metode planiranih eksperimenata i metodologije odzivnih površina i to sadržaja vode, temperature, mase vezanog enzima na nosaču, početnog molarnog odnosa reaktanata i trenutka dodavanja molekulskih sita u sistem. Sinteza estara je optimizovana, izvršena je ocena značajnosti parametara i utvrđen je adekvatan matematički model na osnovu koga se može predvideti ponašanje sistema (prinos estara) u funkciji navedenih faktora.