LAUSR

Abstract We present theory for electrolysis at electrode surfaces modified by a layer of electroactive enzyme which can mediate the reduction of a substrate to a product. In particular, we compare and contrast immobilisation on flat surfaces with that on porous surfaces. We identify the conditions under which the adoption of porous electrodes facilitates markedly improves turnover rates and develop the analysis on the basis of the porous layer conferring a much-increased effective surface coverage. For both types of electrode, the role of the electrode potential in controlling the thermodynamics of the binding of the substrate with the reduced layer of immobilised enzymes is quantified, and the observation of apparent potential dependent Michaelis constants are explained. Four distinct classes of voltammetric responses are categorised allowing bottom-up process optimisation.