Biochar application to topsoil has been repeatedly and independently reported to reduce N2O emissions, yet the underlying mechanisms remain poorly understood. This study hypothesizes that biochar enhances the stability and catalytic activity of N2O reductase enzymes in denitrifying bacteria, promoting the conversion of N2O to N2 during denitrification. Interactions between biochar and the N2O reductase enzyme (PsN2OR) from the denitrifying bacterium Pseudomonas stutzeri were investigated through molecular dynamics simulations. The obtained results firstly revealed that biochar stabilizes this periplasmic enzyme in the aqueous solution via hydrophobic and hydrophilic interactions. Specifically, π–π stacking and hydrophobic interactions reduce the thermal fluctuations of hydrophobic amino acids, lowering entropy and improving enzymatic efficiency. Additionally, biochar adsorbs N2O molecules, facilitating their delivery to the active site of the enzyme and enhancing the reaction rate. Deeper understandings of molecular interactions open new pathways in developing biochar-based fertilizers with slower, more economically and more environmentally favorable release of nutrients. This new type of fertilizers creates new opportunities for the biochar market, positioning it as a valuable tool for carbon sequestration and the mitigation of N₂O emissions.

中文翻译：

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了解生物炭和反硝化剂在减少 N₂O 排放中相互作用的分子机制：更经济和可持续肥料的途径


生物炭应用于表层土壤以减少 N2O 排放的报道已一再独立，但其潜在机制仍然知之甚少。本研究假设生物炭增强了反硝化细菌中 N2O 还原酶的稳定性和催化活性，促进反硝化过程中 N2O 向 N2 的转化。通过分子动力学模拟研究了生物炭与反硝化细菌 Pseudomonas stutzeri 的 N2O 还原酶 （PsN2OR） 之间的相互作用。获得的结果首先揭示了生物炭通过疏水和亲水相互作用稳定了水溶液中的这种周质酶。具体来说，π-π 堆叠和疏水相互作用减少了疏水氨基酸的热波动，降低了熵，提高了酶效率。此外，生物炭吸附 N2O 分子，促进它们递送到酶的活性位点并提高反应速率。对分子相互作用的更深入理解为开发基于生物炭的肥料开辟了新的途径，这些肥料具有更慢、更经济和更环保的营养物质释放。这种新型肥料为生物炭市场创造了新的机会，使其成为碳封存和减少 N₂O 排放的宝贵工具。