View article

In recent years enzymes have found widespread use in areas as diverse as chemical synthesis,[1–3] decontamination of waste streams,[4] and biosensors.[5, 6] For ease of application and for stabilization purposes, enzymes are often immobilized on solid supports. These supports can include inorganic substrates such as silicon [7, 8] or glass,[9] as well as organic materials such as polymers [10] or hydrogels.[11] In current industrial processes, enzymes are often simply adsorbed onto the material. Although this is a cost-effective method for supporting enzymes, these biocatalytic materials often suffer from decreased activity after prolonged usage because of the leakage of adsorbed enzymes during catalysis and recycling. Furthermore, since there is a lack of control over the enzyme positioning, only a fraction of the enzyme is in contact with the environment and therefore used effectively. In more sophisticated applications, such as sensors and analytical devices, covalent immobilization is achieved using carefully designed anchors [8] and surface modification.[7] These multistep procedures lead to welldefined systems, but costs are raised considerably and these methods are difficult to extend to large-scale applications. In this article we describe a simple and effective strategy for immobilizing enzymes covalently onto a solid porous support, and ascertain that a large fraction of the enzyme is available for catalysis. To achieve this, a support with a high surface to volume ratio is employed, namely a polymerized high internal phase emulsion (polyHIPE). N-Hydroxysuccinimide esters are introduced into this highly porous monolithic support for …