Use of Self‐Assembled Monolayers for the Sequential and Independent Immobilisation of Enzymes

Abstract

Dedicated to our friend and colleague, Prof. Wolfgang Schuhmann on the occasion of his 65 th birthdayThe precise spatial control of the immobilisation of enzymes is necessary for the sequential localisation of an enzymatic cascade. In this contribution, the sequential immobilisation of alcohol dehydrogenase (ADH), formaldehyde dehydrogenase (FLDH) and formate dehydrogenase (FoDH) on self-assembled monolayer modified electrodes has been demonstrated. A range of thiols were screened and optimal enzymatic activity was obtained with thiols bearing -OH, a positively charged heterocyclic aromatic ring and -COOH for the immobilisation of ADH, FLDH and FoDH, respectively. Scanning of the applied potential was utilised to separately modify individual electrodes with the appropriate thiol and enzyme to deliver a threeenzyme system with catalytically active enzyme. Immobilised ADH, FLDH and FoDH retained 46, 32 and 76 % of initial activity, respectively, on storage in aqueous solution at 4 °C for a period of two weeks.

A Conductive Microcavity Created by Assembly of Carbon Nanotube Buckypapers for Developing Electrochemically Wired Enzyme Cascades

“…This is achieved by maximizing the number of electrons during the oxidation or reduction of the substrate molecule. One-pot reaction based on enzyme cascades in a single platform enables the deep oxidation of biofuels or the production of value-added products without the need to separate intermediates [ 7 , 8 ]. Recently, artificial multienzyme systems have been used to construct bioelectrodes that include an integrated one-pot catalytic system [ 1 , 2 , 9 , 10 ].…”

Electrochemical Immobilisation of Glucose Oxidase for the Controlled Production of H2O2 in a Biocatalytic Flow Reactor

“…[11] Electrochemically prepared self-assembled monolayers were used to sequentially and independently immobilise alcohol dehydrogenase (ADH), formaldehyde dehydrogenase (FLDH), and formate dehydrogenase (FoDH) on three separate electrodes. [28] Hydrogen peroxide (H 2 O 2 ) can be considered as an environmentally friendly oxidant in chemical synthesis. [29] It provides 47 % of its mass as an oxidant, and water and oxygen are the only by-products in the reaction.…”

“…In a flow reactor, the hydrolysis of 4‐nitrophenyl butyrate (4‐NPB) was achieved with 100 % conversion efficiency [11] . Electrochemically prepared self‐assembled monolayers were used to sequentially and independently immobilise alcohol dehydrogenase (ADH), formaldehyde dehydrogenase (FLDH), and formate dehydrogenase (FoDH) on three separate electrodes [28] …”