Immobilization in Ionogel: A New Way to Improve the Activity and Stability of <i>Candida antarctica</i> Lipase B

Abstract

New Candida antarctica lipase B derivatives with higher activity than the free enzyme were obtained by occlusion in an organogel of an ionic liquid (ionogel) based on the ionic liquid [Omim][PF6] and polyvinyl chloride. The inclusion of glutaraldehyde as a crosslinker improved the properties of the ionogel, allowing the enzymatic derivative to reach 5-fold higher activity than the free enzyme and also allowing it to be reused at 70 °C. The new methodology allows enzymatic derivatives to be designed by changing the ionic liquid, thus providing a suitable microenvironment for the enzyme. The ionic liquid may act on substrates to increase their local concentration, while reducing water activity in the enzyme’s microenvironment. All this allows the activity and selectivity of the enzyme to be improved and greener processes to be developed. The chemical composition and morphology of the ionogel were also studied by scanning electron microscopy–energy dispersive X-ray spectroscopy, finding that porosity, which was related with the chemical composition, was a key factor for the enzyme activity.

Keywords

• enzymatic immobilization
• organogels
• ionogels
• ionic liquid
• ester synthesis
• enzyme