# Immobilization of TthLPMO9G on Carbon Felt for Potential Electrochemical Applications

## TL;DR

Researchers immobilized an enzyme on carbon felt to study its electrochemical activity for potential bioelectrocatalytic applications.

## Contribution

A novel approach to immobilize TthLPMO9G on carbon felt for bioelectrocatalysis is presented with insights into its limitations.

## Key findings

- TthLPMO9G was successfully immobilized on carbon felt using covalent bonding after surface oxidation.
- Electrochemical activity of immobilized TthLPMO9G was detectable only via FTacV, not cyclic voltammetry.
- Direct electron transfer remains challenging, highlighting limitations in current immobilization strategies.

## Abstract

This study explores
the entrapment, immobilization, and direct
electron transfer-type bioelectrocatalysis mediated by TthLPMO9G on carbon-based electrode materials, focusing on carbon felt
(CF) due to its high conductivity, chemical stability, and large surface
area. At first, entrapment of an LPMO from Thermohelomyces
thermophila,TthLPMO9G was achieved
using Nafion-coated carbon fibers. At the next step, CF electrodes
were chemically oxidized to introduce carboxyl groups, quantified
by conductometric titration, and used for covalent immobilization
of the enzyme. The immobilization process for TthLPMO9G was optimized, and the catalytic activity was assessed based
on cellulose oxidation. The success of the immobilization process
was evaluated using three parameters: yield (%), efficiency (%), and
%recovery (%). Electrochemical studies, including cyclic voltammetry
(CV) and Fourier-transform alternating current voltammetry (FTacV),
were performed to evaluate TthLPMO9G’s electrochemical
activity. Immobilized LPMO activity was detectable only through the
more sensitive FTacV. Direct electron transfer (DET) from the electrode
to the enzyme active site remains a challenge. This work provides
insight into the limitations of the studied strategies in LPMO-based
electrocatalysis, thus offering guidance for improving immobilization
process and electrochemical integration in future applications targeting
DET bioelectrocatalysis.