Unassisted solar lignin valorisation using a compartmented photo-electro-biochemical cell

Abstract

Lignin is a major component of lignocellulosic biomass. Although it is highly recalcitrant to break down, it is a very abundant natural source of valuable aromatic carbons. Thus, the effective valorisation of lignin is crucial for realising a sustainable biorefinery chain. Here, we report a compartmented photo-electro-biochemical system for unassisted, selective, and stable lignin valorisation, in which a TiO2 photocatalyst, an atomically dispersed Co-based electrocatalyst, and a biocatalyst (lignin peroxidase isozyme H8, horseradish peroxidase) are integrated, such that each system is separated using Nafion and cellulose membranes. This cell design enables lignin valorisation upon irradiation with sunlight without the need for any additional bias or sacrificial agent and allows the protection of the biocatalyst from enzyme-damaging elements, such as reactive radicals, gas bubbles, and light. The photo-electro-biochemical system is able to catalyse lignin depolymerisation with a 98.7% selectivity and polymerisation with a 73.3% yield using coniferyl alcohol, a lignin monomer.

High-Value Chemicals from Electrocatalytic Depolymerization of Lignin: Challenges and Opportunities

“…The integration of electro(photo)chemical generation of H 2 O 2 system with enzymatic catalysis is known to improve the process efficiency. Lignin peroxidase has also been used for depolymerization of β-O-4 lignin model compound and lignin in a three-compartment cell separated with Nafion and cellulose membranes together with TiO 2 photocatalyst and Co-N/CNT as an electrocatalyst ( Figure 1 ) [ 54 ]. This photoelectrobiochemical system enabled lignin dimer cleavage with high conversion efficiency (93.7%) and selectivity (98.7%) to 3,4-dimethylbenzaldehyde.…”

Green and sustainable route for oxidative depolymerization of lignin: New platform for fine chemicals and fuels

“…Furthermore, the photo-electrobiochemical design is catalyzed the lignin depolymerization with a 98.7% selectivity and polymerization with a 73.3% yield using a lignin monomer: coniferyl alcohol. 59 In other side, the metal free organocatalytic approach for photocatalytic depolymerization of lignin monomer was developed. In this method N-phenylpheno-thiazine (PhPTH) was identified as a photocatalyst for the valorization of β-O-4 linkages in lignin monomer under irradiation of violet or Kessil LED's offered the aromatic monomers in high yields.…”

Intervening Bismuth Tungstate with DNA Chain Assemblies: A Perception toward Feedstock Conversion via Photoelectrocatalytic Water Splitting

“…In the literature, oxygen evaluation or hydrogen evolution, followed by their utilization for organic transformation, is of current interest. ,, Along this line, after successful application of our designed Bi 2 WO 6 @DNA-2 as photoanodes in PEC water splitting, for the first time, an idea with the real-life application of the produced hydrogen is tested for feedstock conversion. For this study, the large-scale conversion of feedstock materials to value-added chemicals by photocatalytic hydrogenation/hydrogenolysis reaction is demonstrated under external hydrogen pressure.…”

“…There were no reports to carry both PEC water splitting and feedstock conversion using the same catalyst in the literature. Ko et al recently reported the photoelectro-biochemical feedstock conversion with lignin model compound . They have studied in-situ-generated H 2 O 2 from a three-compartment photoelectro-biochemical reactor for stable and selective lignin valorization .…”