Preparation and Characterization of Enzyme Compartments in UV-Cured Polyurethane-Based Materials and Their Application in Enzymatic Reactions.

Diana Uhrich,Jan Von Langermann

doi:10.3389/fmicb.2017.02111

Abstract

The preparation and characterization of UV-cured polyurethane-based materials for the mild inclusion immobilization of enzymes was investigated. Full curing of the polymer precursor/enzyme solution mixture was realized by a short irradiation with UV-light at ambient temperatures. The included aqueous enzyme solution remains highly dispersed in the polymer material with an even size distribution throughout the polymer material. The presented concept provides stable enzyme compartments which were applied for an alcohol dehydrogenase-catalyzed reduction reaction in organic solvents. Cofactor regeneration was achieved by a substrate-coupled approach via 2-propanol or an enzyme-coupled approach by a glucose dehydrogenase. This reaction concept can also be used for a simultaneous application of contrary biocatalytic reaction conditions within an enzymatic cascade reaction. Independent polymer-based reaction compartments were provided for two incompatible enzymatic reaction systems (alcohol dehydrogenase and hydroxynitrile lyase), while the relevant reactants diffuse between the applied compartments.

Highlights

Enzymes are highly versatile biocatalysts that catalyze a vast variety of reactions under typically mild reaction conditions (Faber, 2004; Tao and Kazlauskas, 2011)
The shown enzyme compartments were obtained by UV-light curing of an emulsion of a hydrophobic polyurethane precursor and an aqueous enzyme solution
Based on the formed initial emulsion the incorporated aqueous domains of the enzyme solution remain stable and finely dispersed in the polymer matrix, which itself is stable against various solvents

Summary

Introduction

Enzymes are highly versatile biocatalysts that catalyze a vast variety of reactions under typically mild reaction conditions (Faber, 2004; Tao and Kazlauskas, 2011) In their natural environment these enzymes are often localized within cellular or subcellular domains (microenvironment compartmentalization), which provides optimal conditions for the respective reaction, e.g., pH and availability of (co-)substrates, cofactors, etc. Eukaryotic cells are based on a complex of membranes and other compartments, which are specialized for the required biological functions (Huh et al, 2003; Barabási and Oltvai, 2004) These compartments are not necessarily permanent, as found in the metabolic cycle of yeast, which features temporal compartments (Tu et al, 2005). Such permanent and temporal compartments allow within a complex orchestra of reaction pathways biological systems to perform anabolic and catabolic processes in a coordinated approach

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