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Effect of temperature on methane oxidation and community composition in landfill cover soil.
Journal of Industrial Microbiology & Biotechnology ( IF 3.4 ) Pub Date : 2019-07-17 , DOI: 10.1007/s10295-019-02217-y
Krishna R Reddy 1 , Raksha K Rai 1 , Stefan J Green 2 , Jyoti K Chetri 1
Affiliation  

Municipal solid waste (MSW) landfills are the third largest anthropogenic source of methane (CH4) emissions in the United States. The majority of CH4 generated in landfills is converted to carbon dioxide (CO2) by CH4-oxidizing bacteria (MOB) present in the landfill cover soil, whose activity is controlled by various environmental factors including temperature. As landfill temperature can fluctuate substantially seasonally, rates of CH4 oxidation can also vary, and this could lead to incomplete oxidation. This study aims at analyzing the effect of temperature on CH4 oxidation potential and microbial community structure of methanotrophs in laboratory-based studies of landfill cover soil and cultivated consortia. Soil and enrichment cultures were incubated at temperatures ranging from 6 to 70 °C, and rates of CH4 oxidation were measured, and the microbial community structure was analyzed using 16S rRNA gene amplicon sequencing and shotgun metagenome sequencing. CH4 oxidation occurred at temperatures from 6 to 50 °C in soil microcosm tests, and 6-40 °C in enrichment culture batch tests; maximum rates of oxidation were obtained at 30 °C. A corresponding shift in the soil microbiota was observed, with a transition from putative psychrophilic to thermophilic methanotrophs with increasing incubation temperature. A strong shift in methanotrophic community structure was observed above 30 °C. At temperatures up to 30 °C, methanotrophs from the genus Methylobacter were dominant in soils and enrichment cultures; at a temperature of 40 °C, putative thermophilic methanotrophs from the genus Methylocaldum become dominant. Maximum rate measurements of nearly 195 μg CH4 g-1 day-1 were observed in soil incubations, while observed maximum rates in enrichments were significantly lower, likely as a result of diffusion limitations. This study demonstrates that temperature is a critical factor affecting rates of landfill soil CH4 oxidation in vitro and that changing rates of CH4 oxidation are in part driven by changes in methylotroph community structure.

中文翻译:

温度对垃圾掩埋场甲烷氧化和群落组成的影响。

城市固体垃圾(MSW)垃圾填埋场是美国第三大人为甲烷(CH4)排放源。垃圾填埋场中产生的大部分CH4通过垃圾掩埋场土壤中存在的CH4氧化细菌(MOB)转化为二氧化碳(CO2),其活动受各种环境因素(包括温度)控制。由于垃圾填埋场的温度可能会随季节大幅波动,因此CH4的氧化速率也会发生变化,这可能导致氧化不完全。本研究旨在通过实验室研究掩埋土壤和耕种财团的方法,分析温度对甲烷氧化菌的CH4氧化电位和微生物群落结构的影响。将土壤和富集培养物在6至70°C的温度下孵育,并测量CH4氧化速率,利用16S rRNA基因扩增子测序和shot弹枪基因组测序对微生物群落结构进行了分析。在土壤微观测试中,CH4氧化发生在6至50°C的温度下;在浓缩培养分批测试中,发生在4-40°C的温度下;在30°C时可获得最大氧化速率。观察到土壤微生物区系发生了相应的变化,随着培养温度的升高,从推定的嗜甲烷菌向嗜热甲烷菌转变。高于30°C时,甲烷营养群落结构发生了强烈变化。在高达30°C的温度下,甲基杆菌属的甲烷营养菌在土壤和富集培养物中占主导地位。在40°C的温度下,来自Methylocaldum属的推定嗜热甲烷菌成为优势菌。在土壤培养中观察到最大速率测量值接近195μgCH4 g-1 day-1,而观察到的最大富集速率则明显更低,这可能是由于扩散限制所致。这项研究表明,温度是影响垃圾填埋场土壤CH4体外氧化速率的关键因素,CH4氧化速率的变化部分受甲基营养菌群落结构变化的驱动。
更新日期:2019-11-01
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