Zulqarnain Haider Khan,Han Yu,Hui Li,Syed Shabi Ul Hassan Kazmi,Ruixia Han,Muhammad Azeem,Xin Sun,Zia Ur Rehman,Gang Li
Reactive oxygen species (ROS) are critical mediators of soil biogeochemical processes. While the production of ROS with biochar (BC) in the rhizosphere has not been explored. We demonstrate that BC and Fe-modified biochar (FeBC), prepared at 400°C and 600°C, influence ROS generation in paddy soil containing biodegradable (polybutylene succinate: PBS) and conventional (polystyrene) microplastics (MPs). FeBC, particularly FeBC prepared at 600°C, enhance ROS (O 2 •− , H 2 O 2 , • OH) production in paddy soil. The results of rhizosphere-focused pot experiment simulating field-like flooded conditions highlight that FeBC significantly increased O 2 •− , H 2 O 2 , • OH concentrations, especially with PBS (25.63, 27.69, 35.82 µM/kg, respectively) surpassing control by 3.1–3.6-folds. Iron plaque formation, water-soluble phenols, and microbial activity further influenced ROS dynamics and accelerated MP degradation via oxidative fragmentation (SEM surface fissures), dissolved organic carbon release (484 mg/kg), and SUVA 254 decline (4.6 folds). Microbial shifts toward Actinobacteria (37–43 %) and Firmicutes (25–28 %) correlated with ROS dynamics, linking biotic-abiotic degradation pathways. This work reveals the novel role of FeBC in rhizosphere ROS generation and the environmental behavior of MPs in BC-treated agricultural systems.
The potential applications of lytic polysaccharide monooxygenases (LPMOs) in biomass degradation have garnered significant interest. In this study, we characterized AfLPMO 8, a novel AA9 family protein derived from Aspergillus fumigatus Z5. AfLPMO 8 demonstrated the ability to bind copper and enhanced its melting temperature ( Tm ) by 17.7 °C. MALDI-TOF-MS analysis revealed that AfLPMO 8 efficiently cleaved phosphoric acid swollen cellulose (PASC) at the C1 and C4 carbons. Additionally, AfLPMO 8 exhibited significant activity on filter paper, effectively dispersing it. When combined with glycoside hydrolases, AfLPMO 8 markedly improved the hydrolysis efficiency of various agricultural residues, such as corn, rice, soybean, and wheat straw. Furthermore, GRAMM docking analysis showed that Tyr51 in Nc CDH might facilitate electron transfer to the copper ion active center of AfLPMO 8. Ultimately, the identification of AfLPMO 8 might have significant implications for developing novel enzymes for a range of industrial uses, especially in the biofuel and biorefinery sectors.
危险品化学品经营许可证（带存储）