State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China.
State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China.
Water Res. 2024 Sep 1;261:122022. doi: 10.1016/j.watres.2024.122022. Epub 2024 Jun 29.
Controllable and recyclable magnetic porous microspheres (MPMs) have been proposed as a means for enhancing the anaerobic digestion (AD) of sludge, as they do not require continuous replenishment and can serve as carriers for anaerobes. However, the effects of MPMs on the interfacial thermodynamics of sludge and the biological responses triggered by abiotic effects in AD systems remain to be clarified. Herein, the underlying mechanisms by which MPMs alter the solid-liquid interface of sludge to drive methanogenesis were investigated. A significant increase in the contents of C and H (D) in methane molecules was observed in the presence of MPMs, suggesting that MPMs might enhance the CO-reduction methanogenesis and participation of water in methane generation. Experimental results demonstrated that the addition of MPMs did not promote the anaerobic bioconversion of soluble organics for methanogenesis, suggesting that the enhanced methanogenesis and water participation were not achieved through promotion of the bioconversion of original liquid-state organics in sludge. Analyses of the capillary force, surface adhesion force, and interfacial proton-coupled electron transfer (PCET) of MPMs revealed that MPMs can enhance mass transfer, effective contact, and electron-proton transfer with sludge. These outcomes were confirmed by the statistical analyses of variations in the interfacial thermodynamics and PCET of sludge with and without MPMs during AD. It was thus proposed that the MPMs enhanced the PCET of sludge and PCET-driven release of protons from water by promoting the interfacial Lewis acid-base interactions of sludge, thereby resulting in the enrichment of free and attached methanogenic consortia and the high energy-conserving metabolic cooperation. This proposition was further confirmed by identifying the predominant syntrophic partners, suggesting that PCET-based efficient methanogenesis was attributable to the enrichment of genomes harbouring CO-reducing pathway and genes encoding water-mediated proton transfer. These findings offer new insights into how substrate properties can be altered by exogenous materials to enable highly efficient methanogenesis.
可控制和可回收的磁性多孔微球（MPMs）已被提议作为增强污泥厌氧消化（AD）的一种手段，因为它们不需要连续补充，并且可以作为厌氧菌的载体。然而，MPMs 对污泥固液界面的影响以及 AD 系统中无生命效应引发的生物响应仍有待澄清。在此，研究了 MPMs 改变污泥固液界面以驱动产甲烷作用的潜在机制。在 MPMs 的存在下，甲烷分子中的 C 和 H（D）含量显著增加，这表明 MPMs 可能增强 CO 还原产甲烷作用和水参与甲烷生成。实验结果表明，添加 MPMs 并没有促进可溶性有机物的厌氧生物转化用于产甲烷作用，这表明增强的产甲烷作用和水参与不是通过促进污泥中原始液态有机物的生物转化来实现的。对 MPMs 的毛细力、表面粘附力和界面质子耦合电子转移（PCET）的分析表明，MPMs 可以增强质量传递、与污泥的有效接触和电子质子转移。这些结果通过 AD 过程中有无 MPMs 时污泥界面热力学和 PCET 的统计分析得到了证实。因此，提出 MPMs 通过促进污泥的界面路易斯酸碱相互作用，增强了污泥的 PCET 和 PCET 驱动的水从质子释放，从而导致游离和附着的产甲烷菌群的富集和高能量保存的代谢合作。这一说法通过鉴定主要的共生伙伴得到了进一步证实，这表明基于 PCET 的高效产甲烷作用归因于富含 CO 还原途径基因组和编码水介导质子转移的基因的富集。这些发现为外源材料如何改变底物性质以实现高效产甲烷作用提供了新的见解。
