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

• Main Authors: Yuki Sakurada, Kouta Takeda, Hiroyuki Ohno, Nobuhumi Nakamura
• Format: Article
• Language: English
• Published: MDPI AG 2017-10-01
• Series: Catalysts
• Subjects: biofuel cells; quinoproteins; pyrroloquinoline quinone; alcohol dehydrogenase; polyion complex; redox mediator; gold nanoparticles
• Online Access: https://www.mdpi.com/2073-4344/7/10/296

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.