Zhang Wei, Alessi Anna M, Heaven Sonia, Chong James P J, Banks Charles J
Faculty of Engineering and Physical Sciences, University of Southampton, Southampton SO17 1BJ, UK.
Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK; Biorenewables Development Centre Ltd., 1 Hassacarr Close, Chessingham Park, Dunnington, York YO19 5SN, UK.
Waste Manag. 2021 Nov;135:409-419. doi: 10.1016/j.wasman.2021.09.017. Epub 2021 Oct 4.
Transitions in microbial community structure in response to increasing ammonia concentrations were determined by monitoring mesophilic anaerobic digesters seeded with a predominantly acetoclastic methanogenic community from a sewage sludge digester. Ammonia concentration was raised by switching the feed to source segregated domestic food waste and applying two organic loading rates (OLR) and hydraulic retention times (HRT) in paired digesters. One of each pair was dosed with trace elements (TE) known to be essential to the transition, with the other unsupplemented digester acting as a control. Samples taken during the trial were used to determine the metabolic pathway to methanogenesis using C labelled acetate. Partitioning of C between the product gases was interpreted via an equation to indicate the proportion produced by acetoclastic and hydrogenotrophic routes. Archaeal and selected bacterial groups were identified by 16S rRNA sequencing, to determine relative abundance and diversity. Acclimatisation for digesters with TE was relatively smooth, but OLR and HRT influenced both metabolic route and community structure. The C ratio could be used quantitatively and, when interpreted alongside archaeal community structure, showed that at longer HRT and lower loading Methanobacteriaceae were dominant and hydrogenotrophic activity accounted for 77% of methane production. At the higher OLR and shorter HRT, Methanosarcinaceae were dominant with the C ratio indicating simultaneous production of methane by acetoclastic and hydrogenotrophic pathways: the first reported observation of this in digestion under mesophilic conditions. Digesters without TE supplementation showed similar initial changes but, as expected failed to complete the transition to stable operation.
通过监测接种了来自污水污泥消化器的主要以乙酸裂解产甲烷菌群落的中温厌氧消化器，确定了微生物群落结构随氨浓度增加的转变情况。通过将进料切换至源头分类的家庭食物垃圾，并在成对的消化器中应用两种有机负荷率（OLR）和水力停留时间（HRT）来提高氨浓度。每对中的一个消化器添加已知对转变至关重要的微量元素（TE），另一个未添加的消化器作为对照。试验期间采集的样品用于使用碳标记的乙酸盐确定产甲烷的代谢途径。通过一个方程式解释产物气体之间的碳分配，以表明由乙酸裂解途径和氢营养途径产生的比例。通过16S rRNA测序鉴定古菌和选定的细菌群，以确定相对丰度和多样性。添加TE的消化器的适应过程相对平稳，但OLR和HRT影响了代谢途径和群落结构。碳比率可以进行定量使用，并且与古菌群落结构一起解释时表明，在较长的HRT和较低的负荷下，甲烷杆菌科占主导地位，氢营养活性占甲烷产量的77%。在较高的OLR和较短的HRT下，甲烷八叠球菌科占主导地位，碳比率表明乙酸裂解途径和氢营养途径同时产生甲烷：这是首次在中温条件下消化过程中报道的此类观察结果。未添加TE的消化器显示出类似的初始变化，但正如预期的那样，未能完成向稳定运行的转变。
