Review of advances in the development of laccases for the valorization of lignin to enable the production of lignocellulosic biofuels and bioproducts

Depolymerization of lignin for biological conversion through sulfonation and a chelator-mediated Fenton reaction

“…28 Enzymes have also been explored for lignin depolymerization, motivated by the overall conversion efficiency of natural lignocellulose breakdown processes, but so far have resulted in very low monomer yields and are also plagued by repolymerization of the breakdown products. 29–34 Thus, there remains a need for economical high yield depolymerization strategies for condensed lignins that result from carbohydrate-first pretreatment processes.…”

Research Progress on Lignocellulosic Biomass Degradation Catalyzed by Enzymatic Nanomaterials

“…Lignin‐degrading enzymes are mainly composed of laccase, manganese peroxidase, lignin peroxidase, and multi‐purpose peroxidase (Figure 4). Laccase can only directly oxidize phenolic lignin units and non‐phenolic subunits and is a typical oxidoreductase for lignin degradation with low redox potential [57] . Under mild conditions, laccase deoxidizes lignin to many substrates, including phenolic compounds, aliphatic amines, aromatic amines, hydroxylamines, and phenylmercaptan, and produces H 2 O as the only by‐product [58] .…”

“…Laccase can only directly oxidize phenolic lignin units and non-phenolic subunits and is a typical oxidoreductase for lignin degradation with low redox potential. [57] Under mild conditions, laccase deoxidizes lignin to many substrates, including phenolic compounds, aliphatic amines, aromatic amines, hydroxylamines, and phenylmercaptan, and produces H 2 O as the only by-product. [58] Laccaseassisted oxidation includes three main steps: [58][59] (i) electron reduction of T 1 copper released by oxidation substrate; (ii) electron transfer from T 1 copper to T 2 /T 3 site; and (iii) T 2 /T 3 site uses electrons to reduce O 2 to H 2 O.…”

Synthetic biology toolkit for engineering Cupriviadus necator H16 as a platform for CO2 valorization

“…With increasing concerns on climate change and sustainability, new concepts such as “Circular Economies” and “Carbon Neutrality” have been proposed to call for the production of chemicals and biofuels from renewable feedstocks [ 1 , 2 ]. However, corn-based biofuel production has triggered a fierce debate on “Food versus Fuel” [ 3 ] and the second-generation biofuels from lignocellulose biomass still suffer from low efficiency and high cost [ 4 ]. Alternatively, CO 2 is generally considered as the third-generation feedstock for biofuels [ 5 ].…”