Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China; Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China.
Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China.
Waste Manag. 2023 Apr 15;161:263-274. doi: 10.1016/j.wasman.2023.02.017. Epub 2023 Mar 12.
Landfill cover soil is the environmental interface between landfills and the atmosphere and plays an important role in mitigating CH emission from landfills. Here, stable isotope probing microcosms with CH or CH and dimethyl sulfide (DMS) were carried out to characterize activity and community structure of methanotrophs in landfill cover soils under DMS stress. The CH oxidation activity in the landfill cover soils was not obviously influenced at the DMS concentration of 0.05%, while it was inhibited at the DMS concentrations of 0.1% and 0.2%. DMS-S was mainly oxidized to sulfate (SO) in the landfill cover soils. In the landfill cover soils, DMS could inhibit the expression of bacteria and decrease the abundances of pmoA and mmoX genes, while it could prompt the expression of pmoA and mmoX genes. γ-Proteobacteria methanotrophs including Methylocaldum, Methylobacter, Crenothrix and unclassified Methylococcaceae and α-Proteobacteria methanotrophs Methylocystis dominated in assimilating CH in the landfill cover soils. Of them, Methylobacter and Crenothrix had strong tolerance to DMS or DMS could promote the growth and activity of Methylobacter and Crenothrix, while Methylocaldum had weak tolerance to DMS and showed an inhibitory effect. Metagenomic analyses showed that methanotrophs had the genes of methanethiol oxidation and could metabolize CH and methanethiol simultaneously in the landfill cover soils. These findings suggested that methanotrophs might metabolize sulfur compounds in the landfill cover soils, which may provide the potential application in engineering for co-removal of CH and sulfur compounds.
垃圾填埋场覆盖土是填埋场与大气之间的环境界面，在减轻填埋场 CH 排放方面起着重要作用。在这里，进行了含有 CH 或 CH 和二甲基硫（DMS）的稳定同位素探测微宇宙实验，以表征在 DMS 胁迫下垃圾填埋场覆盖土中甲烷氧化菌的活性和群落结构。当 DMS 浓度为 0.05%时，垃圾填埋场覆盖土中的 CH 氧化活性没有明显受到影响，而当 DMS 浓度为 0.1%和 0.2%时，CH 氧化活性受到抑制。在垃圾填埋场覆盖土中，DMS-S 主要被氧化为硫酸盐（SO）。在垃圾填埋场覆盖土中，DMS 可以抑制细菌的表达，降低 pmoA 和 mmoX 基因的丰度，同时可以促进 pmoA 和 mmoX 基因的表达。γ-变形菌甲烷氧化菌包括 Methylocaldum、Methylobacter、Crenothrix 和未分类的 Methylococcaceae 以及 α-变形菌甲烷氧化菌 Methylocystis 是垃圾填埋场覆盖土中主要的 CH 同化菌。其中，Methylobacter 和 Crenothrix 对 DMS 具有较强的耐受性，或者 DMS 可以促进 Methylobacter 和 Crenothrix 的生长和活性，而 Methylocaldum 对 DMS 的耐受性较弱，表现出抑制作用。宏基因组分析表明，甲烷氧化菌具有甲硫醇氧化基因，可以同时代谢 CH 和甲硫醇。这些发现表明，甲烷氧化菌可能会代谢垃圾填埋场覆盖土中的硫化合物，这可能为工程上同时去除 CH 和硫化合物提供了潜在的应用。
