Aug 2026· Bioresource Technology· Vol 463, pp.
135734
· 0 citations· 48 references
Medicine
TL;DR
This study systematically elucidates the synergistic lignin conversion mechanism of CDGs by a fungal consortium from structural, enzymatic, and metabolic perspectives, uncovering a temporal division of labor together with new lignin catabolic pathways that provide a mechanistic framework for the biological valorization of lignocellulosic biomass.
Abstract
Chinese Distillers' grains (CDGs), a typical agro-industrial byproduct, contain a highly recalcitrant lignin that limits the utilization. In this study, a dual-fungal solid-state fermentation system consisting of Phanerochaete chrysosporium and Pleurotus eryngii was constructed for lignin conversion in CDGs. The lignin degradation ratio reached 58.66%, indicating that the system can effectively convert lignin. Laccase (Lac) and manganese peroxidase (MnP) activities peaked at 10 d, reaching 38.54 and 50.36 U/g, respectively, whereas lignin peroxidase (LiP) reached its maximum activity (51.67 U/g) at 15 d. Integrated transcriptomic and metabolomic analyses revealed a clear temporal division of labor between the dual-fungal. During the early stage, P. chrysosporium predominantly expressed AA2 family peroxidase genes, promoting oxidative cleavage of lignin β-O-4 linkages and the generation of aromatic intermediates. In contrast, P. eryngii became dominant during the middle and late stages through the upregulation of AA1 family laccase genes and aromatic catabolic pathways, facilitating the further conversion of lignin-derived compounds. Metabolic pathway reconstruction showed that H- and G-type lignin-derived intermediates converged into 1,2,4-benzenetriol, whereas S-type lignin-derived was primarily degraded through the gallic acid pathway. This study systematically elucidates the synergistic lignin conversion mechanism of CDGs by a fungal consortium from structural, enzymatic, and metabolic perspectives, uncovering a temporal division of labor together with new lignin catabolic pathways that provide a mechanistic framework for the biological valorization of lignocellulosic biomass.
Chinese distillers’ grains (CDGs) are a lignocellulose-rich agricultural byproduct with considerable bioconversion potential; however, their recalcitrant structure imposes a major bottleneck for efficient valorization. In this study, six white-rot fungal strains and two Trichoderma strains were isolated from wild macrofungi, among which Ganoderma sp. 2G1-6 exhibited the highest laccase activity, reaching 11.29 U/mL. Whole-genome sequencing revealed a 49.15 Mb genome containing 12,437 predicted proteins, including a substantial repertoire of 196 glycoside hydrolases and 113 auxiliary activity enzymes implicated in lignocellulose degradation. Solid-state fermentation of CDGs with Ganoderma sp. 2G1-6 produced high enzyme activities, including endoglucanase (13.3 ± 4.6 U/g), xylanase (538.8 ± 33.0 U/g), β-glucosidase (26,572 ± 2996 U/g), and laccase (231.2 ± 16.7 U/g). Concomitantly, the nutritional profile of CDGs was markedly improved after 30 days, with crude protein increasing by 28.51%, acid-soluble protein by 33.33%, and soluble dietary fiber by 159%. Complementary structural analyses (FTIR, SEM, XRD, and TGA) confirmed progressive disruption of the lignocellulosic matrix, selective delignification, and enhanced cellulose exposure. These findings establish Ganoderma sp. 2G1-6 as a promising microbial chassis for CDGs valorization and provide preliminary functional profiles of Ganoderma species for lignocellulose bioconversion.
Yanling Hu, Ling-Zhen Zhou, Y. Wang et al.· Journal of Fungi· 0 citations
Ligninolytic macromycetes are important producers of oxidative enzymes with potential applications in the mycoremediation of synthetic dyes. However, the enzymatic potential of native tropical lignicolous fungi and the optimization of enzyme production for dye degradation remain poorly understood. This study aimed to isolate and characterize native lignicolous fungi, evaluate their ligninolytic enzyme production and dye-degrading [malachite green (MG) and phenol red (PR)] capacity, and optimize enzyme production using response surface methodology. Five fungal isolates were identified as Trametes villosa, Trametes sp., Junghuhnia sp., Pycnoporus sanguineus, and Schizophyllum commune. On PDA, T. villosa exhibited the highest mycelial growth rate (1.16 cm day-1), whereas P. sanguineus showed the highest laccase activity (18.64 U L-1). Under submerged fermentation, P. sanguineus produced the greatest H2O2 (418.9 mg L-1), laccase (398.6 U L-1), and lignin peroxidase (618.3 U L-1) activities; while Junghuhnia sp. exhibited the highest manganese peroxidase (MnP; 32.9 U L-1). Crude enzymatic extracts degraded MG and PR by 94.57% and 47.84%, respectively, within 72 hr. Box-Behnken optimization revealed that high glucose concentrations (30 g L-1) enhanced laccase production in 0.86-fold increase, whereas low yeast extract (1.25 g L-1) favored MnP synthesis in 5.10-fold increase. These findings identify native tropical fungi, particularly P. sanguineus, as promising candidates for enzyme-based wastewater treatment and environmental remediation.
María Monserrat Chávez-Ramírez, Andrea Mendoza-Arceo, Wilberth Chan-Cupul· Preparative Biochemistry & B...· 0 citations
Dark fermentative hydrogen production from lignocellulosic residues is often limited by inefficient electron distribution and competing metabolic pathways. In this study, a lignin-derived humic substance-biochar (LHS-BC) was developed to enhance thermophilic hydrogen production from lignocellulosic residues. Among the tested materials, the lignin-derived humic-like substance obtained via alkaline oxidative humification and subsequently combined with biochar (HSH@BC) exhibited the best performance, increasing hydrogen production (mL/L) by 29.76% compared with the control. Kinetic analysis showed that HSH@BC significantly increased hydrogen production potential (1113.98 mL/L) and reduced lag time. The composite promoted cellulose degradation, enhanced cellulase and hydrogenase activities, and increased intracellular NAD+/NADH levels. Metabolic analysis revealed a shift from ethanol-type fermentation to acetate-butyrate pathways, leading to higher hydrogen yield. Electrochemical characterization suggests that cytochrome c may be involved in electron exchange with the quinone functional groups in LHS-BC. PICRUSt-based functional prediction suggested potential enrichment of central metabolic pathways, including glycolysis, pyruvate metabolism, the tricarboxylic acid (TCA) cycle, and the pentose phosphate pathway (PPP). Overall, LHS-BC improved hydrogen production by simultaneously regulating microbial community structure, metabolic pathways, and electron transfer processes, providing an effective strategy for thermophilic biohydrogen production from lignocellulosic biomass.
Lignin is the most recalcitrant component of the plant cell wall, and its selective removal underpins numerous biotechnological processes ranging from second-generation biofuel production to animal feed upgrading and industrial effluent treatment. White-rot fungi remain the most efficient natural agents of lignin mineralisation, owing to a suite of extracellular oxidoreductases that include laccase, lignin peroxidase, manganese peroxidase and versatile peroxidase. Solid-state fermentation, a cultivation mode that mimics the natural substrate ecology of wood-decaying basidiomycetes, has become the preferred platform for harnessing this ligninolytic machinery at a scale relevant to industry. Yet a persistent obstacle to translating laboratory findings into predictable, scalable outcomes is the substantial variability in enzyme titres and delignification efficiency observed across fungal species, substrates, process configurations and reactor geometries. This review critically synthesises the literature on the ligninolytic performance of white-rot fungi during solid-state fermentation, with particular emphasis on the methods by which such performance can be extrapolated from small-scale screening experiments to pilot- and industrial-scale operation. The enzymatic basis of lignin depolymerisation is first outlined, followed by an appraisal of interspecific and intraspecific variability in enzyme yield. Substrate and process parameters that govern ligninolytic expression are then examined, before the review turns to the principal extrapolation strategies reported in the literature: statistical and response-surface methodologies, kinetic and mechanistic modelling, data-driven and machine-learning approaches, co-cultivation strategies, and bioreactor engineering approaches to scale-up. Applications enabled by reliable extrapolation, spanning biopulping, ruminant nutrition and bioremediation, are discussed alongside the persistent gaps that limit predictive confidence. The review concludes that although substantial empirical knowledge has accumulated regarding the ligninolytic capacities of individual white-rot species, the field still lacks a unifying quantitative framework capable of forecasting enzymatic performance across heterogeneous solid substrates and reactor formats, and it proposes that hybrid mechanistic–data-driven models represent the most promising avenue for closing this gap.
Latika Bhatia· Asian Plant Research Journal· 0 citations
Pseudo-lignin formation severely limits lignocellulose utilization, yet its study is hindered by mixing with unconverted lignocellulosic components. Here, corncob-derived pseudo-lignin was successfully separated for the first time through tetrahydrofuran (THF)/petroleum ether (PE) extraction, providing a basis for the elucidation of the pseudo-lignin formation mechanism. The key intermediate trans-p-coumaric acid (TPCA) from lignin degradation was captured, which plays a crucial role in the formation of pseudo-lignin. In combination with comprehensive characterizations, the reaction network and the structural models of pseudo-lignin were established. Furthermore, through sodium chlorite/acetic acid (SCA) pretreatment to selectively remove lignin, the structural difference between pseudo-lignin formed in the presence of lignin and holocellulose-derived humins formed in the absence of lignin was clearly revealed, verifying that it is the lignin component that introduces the benzene ring structure into pseudo-lignin via its degradation product, while in situ SEM energy-dispersive spectroscopy (EDS) showed pseudo-lignin has a much higher C/O ratio than lignin.
Tianjiao Hu, Jiaxuan Wang, Yang Yang et al.· Journal of Agricultural and...· 0 citations
