Lignin Peroxidase-Catalyzed Selective Cleavage of C-C Bonds in Lignin at Room Temperature

Abstract

Selective oxidative cleavage of C-C linkages is a challenge for chemical transformations including lignin depolymerization. This study reports recombinant Phanerochaete chrysosporium lignin peroxidase isozyme 1 (PcLiP01)-catalyzed nonpolar C-C σ-bond cleavage in lignin model compounds (LMCs), dehydrogenative polymer (DHP), and real milled wood lignin (MWL) to produce a targeted value-added aromatic compound, 2,6-dimethoxy-1,4-benzoquinone (DMBQ) under mild conditions. Notably, according to pH-dependent redox reactions with both phenolic and nonphenolic LMCs, Caryl-Cα cleavage products of the LMCs were dominant under low pH ∼ 3 compared to pH ∼ 5. Furthermore, the oxidative conversion of DHP and MWL using PcLiP01 showed 12 and 5 mg/gsubstrate yields of DMBQ, respectively. These findings offer an approach to support a C-C bond cleavage reaction with less-reactive nonphenolic LMCs and provide valuable insights into the oxidative conversion of lignin to the value-added chemical DMBQ with PcLiP01.