Depolymerization and conversion of lignin to value-added bioproducts by microbial and enzymatic catalysis

Abstract

Lignin, the most abundant renewable aromatic compound in nature, is an excellent feedstock for value-added bioproducts manufacturing; while the intrinsic heterogeneity and recalcitrance of which hindered the efficient lignin biorefinery and utilization. Compared with chemical processing, bioprocessing with microbial and enzymatic catalysis is a clean and efficient method for lignin depolymerization and conversion. Generally, lignin bioprocessing involves lignin decomposition to lignin-based aromatics via extracellular microbial enzymes and further converted to value-added bioproducts through microbial metabolism. In the review, the most recent advances in degradation and conversion of lignin to value-added bioproducts catalyzed by microbes and enzymes were summarized. The lignin-degrading microorganisms of white-rot fungi, brown-rot fungi, soft-rot fungi, and bacteria under aerobic and anaerobic conditions were comparatively analyzed. The catalytic metabolism of the microbial lignin-degrading enzymes of laccase, lignin peroxidase, manganese peroxidase, biphenyl bond cleavage enzyme, versatile peroxidase, and β-etherize was discussed. The microbial metabolic process of H-lignin, G-lignin, S-lignin based derivatives, protocatechuic acid, and catechol was reviewed. Lignin was depolymerized to lignin-derived aromatic compounds by the secreted enzymes of fungi and bacteria, and the aromatics were converted to value-added compounds through microbial catalysis and metabolic engineering. The review also proposes new insights for future work to overcome the recalcitrance of lignin and convert it to value-added bioproducts by microbial and enzymatic catalysis.

Genomic and Experimental Investigations of Auriscalpium and Strobilurus Fungi Reveal New Insights into Pinecone Decomposition

“…Such abilities are common among WR fungi [ 69 ]. For example, the fungi of Ceriporiopsis subvermispora , Phellinus pini , Ganoderma australe , and Phlebia tremellosa specifically degrade lignin and hemicellulose among WR fungi [ 70 ]. The most compelling evidence supporting the early colonizing ability of Auriscalpium fungi is that their number of peptidases S8 and S53 is far greater than that in Strobilurus fungi.…”

Genomic and Experimental Investigations of Auriscalpium and Strobilurus Fungi Reveal New Insights into Pinecone Decomposition

“…Such abilities are common among WR fungi (Floudas, Bentzer, Ahrén, Johansson, & Tunlid, 2020). For example, the fungi ofCeriporiopsis subvermispora , Phellinus pini ,Ganoderma australe , and Phlebia tremellosa specifically degrade lignin and hemicellulose among WR fungi (Weng, Peng, & Han, 2021). The most compelling evidence supporting the early colonizing ability of Auriscalpium fungi is that their number of peptidases S8 and S53 is far greater than that in Strobilurus fungi.…”

Enhanced lignin biodegradation by consortium of white rot fungi: microbial synergistic effects and product mapping

“…Therefore, it is critical to explore efficient approaches to degrade lignin polymer via physical, chemical or biological routes [ 4 ]. As an example for funneling the mixture of monomers by chemo-catalytic methods to produce value-added products, in 2020, Liao et al reported a biorefinery process that converts 78 wt% birch into xylochemicals, which represents one of the major breakthrough towards full utilization of lignin [ 5 , 6 ]. In recent years, great efforts have been made on lignin biodegradation due to its mild condition, diversified choices of microorganisms, and high oxidative potentials.…”