Variations in lignin monomer contents and stable hydrogen isotope ratios in methoxy groups during the biodegradation of garden biomass

Abstract

Lignin is the most difficult aromatic substance to degrade. Selective biodegradation under mild conditions is a promising method, but the dynamic variations in lignin monomers during the biodegradation of lignocellulose are not fully understood. In this study, we examined degradation of lignin monomers and changes in stable hydrogen isotope ratios (δ2HLM) in methoxy groups to test the potential of Pseudomonas mandelii, Aspergillus fumigatus, and their co-culture. The degradation weight loss and net degradation loss of lignocellulosic biomass during biodegradation improved dramatically with fungal inoculation. Syringyl monolignol (S-lignin), which contains two methoxy groups, was more difficult to degrade than guaiacyl (G-lignin), which contains only one methoxy group. The δ2HLM values generally remained stable during the depolymerization of lignin. The fluctuation of δ2HLM values during the initial phase of biodegradation may be related to the loss of pectic polysaccharides (another methoxy donor) from the leaves. Our statistical analysis showed that δ2HLM values did not differ among the microbial cultures or change over time despite decreasing G/S ratios. Our results suggest that lignin monomer ratios can be used to monitor differences in microbial metabolism during lignocellulose biodegradation, whereas δ2HLM signatures cannot be used.

Characteristics of Humic Acids in Drained Floodplain Soils in Temperate Climates: A Spectroscopic Study

“…In floodplain areas where anaerobic conditions could be periodically observed, organic matter transformations are temporarily slowed down, thus further oxidation of -OCH3 does not occur. Defragmentation of the lignin methoxy groups is an important stage of its natural decomposition [82]. The presented results show that in the periodically flooded areas, soil samples do not lose as many -OCH3 groups as in the areas where anaerobic conditions are not observed.…”

Ganoderma lucidum bran-derived blue-emissive and green-emissive carbon dots for detection of copper ions

“…The synthesis of multicolor uorescent CDs from biomass is still an exciting research eld. 34,35 The main component of biomass is lignin, which has the perfect robustness that comes from its remarkable and compact morphology structure. This particular structure makes lignin difficult to pyrolysis, limiting its deep development and utilization.…”