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

• Published in: Biotechnology for biofuels 2021-04, Vol.14 (1), p.84-84, Article 84
• Main Authors: Weng, Caihong, Peng, Xiaowei, Han, Yejun
• Format: Article
• Language: English
• Subjects: Aerobic microorganisms; Alcohol; Anaerobic conditions; Anaerobic microorganisms; Aromatic compounds; Bacteria; Biodegradation; Biological products; Biomass; Bioprocessing; Biorefineries; Biphenyl; Carbon; Catalysis; Catechol; Cellulose; Chemical bonds; Chemical engineering; Chemical engineering research; Chemical properties; Conversion; Decomposition; Degradation; Depolymerization; Enzymatic degradation; Enzymes; Fermentation; Fungi; Heterogeneity; Industrial microorganisms; Laccase; Lignin; Lignin peroxidase; Lignin-derived aromatics; Manganese; Manganese peroxidase; Metabolic engineering; Metabolic pathways; Metabolism; Metabolites; Microbial enzymes; Microbial metabolism; Microorganisms; Peroxidase; Production processes; Protocatechuic acid; Review; Value-added bioproducts; White rot
• ISSN: 1754-6834; 1754-6834
• DOI: 10.1186/s13068-021-01934-w

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.