In order to extract lignin, a novel near-neutral deep eutectic solvent (DES) was developed to treat wheat straw which facilitated its subsequent enzymatic glycation. The DES, whose in situ complexation promotes lignin depolymerization, was composed of choline chloride (ChCl), boric acid (BA), and polyethylene glycol-200 (PEG-200). Our results showed that this kind of DES could dissolve a large amount of lignin and hemicellulose yet retained cellulose well. Under optimum conditions (DES ratio of 1 : 1 : 1.5, 120 °C, 4 h), the proportions of lignin and hemicellulose removed amounted to 88.39% and 84.38%, respectively, with enzymatic digestibility reaching 59.3% in the subsequent enzymatic saccharification with a limited timeframe (5 days) and low enzyme load (30 FPU g⁻¹). The results also demonstrated that lignin's removal rate was positively correlated with the amount of BA used in the DES. The 2D-HSQC NMR, FTIR and TG analyses showed the regenerated lignin to be a typical H–G–S type retaining its intact structure (e.g., β-O-4, β-β, β-5, etc.), whose carbon chain backbone is stable. GPC analysis revealed that this extracted lignin had low molecular weight and a narrower distribution range. Density functional theory showed that BA could bond with –OH similar to Cl⁻, and it occupied more effective sites than Cl⁻ to break the hydrogen-bonding network between lignin and cellulose. Importantly, the DES can be used multiple times without significantly reducing its efficiency, and its structure and properties remain virtually unchanged throughout the use cycle.

White-rot fungus is a common lignin-degrading fungus. However, compared with those of microorganisms that biodegrade lignin alone, synergistic systems of electro-Fenton processes and white-rot fungi are superior because of their high efficiency, mild conditions, and environmental friendliness. To investigate the details of lignin degradation by a synergistic system comprising electro-Fenton processes and white-rot fungi, lignin degradation was studied at different voltages with three lignin-degrading fungi (Phanerochaete chrysosporium, Lentinula edodes, and Trametes versicolor). The lignin degradation efficiency (82∼89%) of the synergistic systems at 4 V was higher than that of a control at 96 h post inoculation. Furthermore, the H₂O₂ produced and phenolic lignin converted in the system can significantly enhance the efficiency of ligninolytic enzymes, so a considerably increased enzyme activity was obtained by the synergistic action of electro-Fenton processes and white-rot fungi. ¹³C NMR spectroscopy revealed that aromatic structure units (103–162 ppm) were effectively degraded by the three fungi. This study shows that the combination of electro-Fenton processes and white-rot fungi treatment significantly improved the lignin degradation efficiency, which established a promising strategy for lignin degradation and valorization.

Hydrogen sulfide (H 2 S) is a toxic and odorous compound present in biogas produced by the anaerobic digestion of biosolids and other organic materials. Elimination of H 2 S is necessary as it is extremely hazardous to human health, poisonous to process catalysts and corrosive to equipment. The desulfurization technology is an important part for efficient utilization of biogas. In this paper, the traditional wet and dry desulfurization technology for biogas was reviewed, and the new research progress of biological desulfurization technologies are also introduced.

The international journal of Aerosol and Air Quality Research (AAQR) covers all aspects of aerosol science and technology, atmospheric science and air quality related issues.