Laccase Encapsulation in ZIF-8 Metal-Organic Framework Shows Stability Enhancement and Substrate Selectivity

Tim-Oliver Knedel; Esther Ricklefs; Carsten Schlüsener; Vlada B Urlacher; Christoph Janiak

doi:10.1002/open.201900146

Laccase Encapsulation in ZIF-8 Metal-Organic Framework Shows Stability Enhancement and Substrate Selectivity

ChemistryOpen. 2019 Jul 18;8(11):1337-1344. doi: 10.1002/open.201900146. eCollection 2019 Nov.

Authors

Tim-Oliver Knedel¹, Esther Ricklefs², Carsten Schlüsener¹, Vlada B Urlacher², Christoph Janiak¹

Affiliations

¹ Institut für Anorganische Chemie und Strukturchemie Heinrich-Heine-Universität Düsseldorf 40204 Düsseldorf.
² Institut für Biochemie Heinrich-Heine-Universität Düsseldorf 40204 Düsseldorf.

Abstract

CgL1 laccase from Corynebacterium glutamicum was encapsulated into the metal-organic framework (MOF) ZIF-8 which was synthesized in a rapid enzyme friendly aqueous synthesis, the fastest in situ encapsulation of laccases reported to date. The obtained enzyme/MOF, i. e. laccase@ZIF-8 composite showed enhanced thermal (up to 70 °C) and chemical (N,N-dimethylformamide) stability, resulting in a stable heterogenous catalyst, suitable for high temperature reactions in organic solvents. Furthermore, the defined structure of ZIF-8 produced a size selective substrate specificity, so that substrates larger than the pore size were not accepted. Thereby, 2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) was used to verify that the enzyme is immobilized inside the MOF versus the outside surface. The enzyme@MOF composite was analyzed by atomic absorption spectroscopy (ASS) to precisely determine the enzyme loading to 2.1 wt%.

Keywords: ZIF-8; enzyme encapsulation; enzyme stabilization; laccase; metal-organic frameworks; substrate specificity.