Immobilization of Pyrroloquinoline Quinone-Dependent Alcohol Dehydrogenase with a Polyion Complex and Redox Polymer for a Bioanode

Abstract

Abstract:A bioanode for ethanol oxidation was prepared by immobilizing the recombinant pyrroloquinoline quinone (PQQ)-dependent alcohol dehydrogenase from Pseudomonas putida KT 2440 (PpADH) with polyion complex (PIC) and redox polymer. The PIC based on poly-L-lysine (PLL) and poly-L-glutamic acid (PGA) was suitable for immobilizing PpADH on the electrode. PpADH was immobilized using only one redox polymer, aminoferrocene, which was attached to the PGA backbone (PGA-AmFc) on the electrode. The anodic current density at 0.6 V (vs. Ag/AgCl) was 22.6 µA·cm −2 . However, when the number of the cycles was increased, the catalytic current drastically decreased. PpADH was immobilized using PGA-AmFc and PIC on the electrode. The anodic current density at 0.5 V (vs. Ag/AgCl) was 47.3 µA·cm −2 , and the performance maintained 74% of the initial value after five cycles. This result indicated that the combination of PIC and PGA-AmFc was suitable for the immobilization of PpADH on the electrode. In addition, the long-term stability and catalytic current density were improved by using the large surface area afforded by the gold nanoparticles.

Environmental applications of immobilized and bio-resourced redox mediators: A Review

“…In biological systems, entrapment has been traditionally considered for the physical retention or fixation of microorganisms and/or enzymes by polymeric carriers such as alginate, nanomaterials, silica gel, polyacrylamide, gelatin, polyion complex, and so on (Moyo et al 2012;Romero-Soto et al 2021). This method keeps the suspended cells and/or enzymes trapped in a porous solid matrix and thus condenses them, preventing their washout or loss from environmental systems or developing enzyme electrodes/biosensors for bioelectrochemical systems (Sakurada et al 2017). Therefore, immobilization using polymeric materials as carriers of bioactive components can improve the efficiency and stability of microorganisms compared to that with free cells and/or enzymes, thus providing a promising technology to mitigate the pollutants in the environment (Fernández-Fernández et al 2013;Somu et al 2022).…”

Biocatalysis and Biotransformations

“…Thus, Tu and coworkers focused on improving the catalytic performance of immobilized lipase on clay/chitosan composites [30]. Sakurada and coworkers increased the long-term stability and catalytic current density of pyrroloquinoline quinone-dependent alcohol dehydrogenase when immobilized on a redox polymer, aminoferrocene, which was attached on an electrode [31]. Finally, several aminated-agarose beads were employed to increase the catalytic efficiency of beta-galactosidases via glutaraldehyde chemistry using different strategies by Zaak and coworkers [32].…”