- 著者
- Shuka Kagemasa Kyohei Kuroda Ryosuke Nakai Yu-You Li Kengo Kubota
- 出版者
- Japanese Society of Microbial Ecology / Japanese Society of Soil Microbiology / Taiwan Society of Microbial Ecology / Japanese Society of Plant Microbe Interactions / Japanese Society for Extremophiles
- 雑誌
- Microbes and Environments (ISSN:13426311)
- 巻号頁・発行日
- vol.37, no.2, pp.ME22027, 2022 (Released:2022-06-08)
- 参考文献数
- 67
- 被引用文献数
- 3
Uncultivated members of Candidatus Patescibacteria are commonly found in activated sludge treating sewage and are widely distributed in wastewater treatment plants in different regions and countries. However, the phylogenetic diversity of Ca. Patescibacteria is difficult to examine because of their low relative abundance in the environment. Since Ca. Patescibacteria members have small cell sizes, we herein collected small microorganisms from activated sludge using a filtration-based size-fractionation approach (i.e., 0.45–0.22 μm and 0.22–0.1 μm fractions). Fractionated samples were characterized using 16S rRNA gene amplicon and shotgun metagenomic sequence analyses. The amplicon analysis revealed that the relative abundance of Ca. Patescibacteria increased to 73.5% and 52.5% in the 0.45–0.22 μm and 0.22–0.1 μm fraction samples, respectively, from 5.8% in the unfractionated sample. The members recovered from the two size-fractionated samples included Ca. Saccharimonadia, Ca. Gracilibacteria, Ca. Paceibacteria, Ca. Microgenomatia, class-level uncultured lineage ABY1, Ca. Berkelbacteria, WS6 (Ca. Dojkabacteria), and WWE3, with Ca. Saccharimonadia being predominant in both fraction samples. The number of operational taxonomic units belonging to Ca. Patescibacteria was approximately 6-fold higher in the size-fractionated samples than in the unfractionated sample. The shotgun metagenomic analysis of the 0.45–0.22 μm fractioned sample enabled the reconstruction of 24 high-quality patescibacterial bins. The bins obtained were classified into diverse clades at the family and genus levels, some of which were rarely detected in previous activated sludge studies. Collectively, the present results suggest that the overall diversity of Ca. Patescibacteria inhabiting activated sludge is higher than previously expected.
- 著者
- Shohei Otomo Akihiko Terada Yu-You Li Kazuya Nishitoba Fumiaki Takakai Kunihiro Okano Naoyuki Miyata Shuhei Masuda
- 出版者
- Japan Society on Water Environment
- 雑誌
- Journal of Water and Environment Technology (ISSN:13482165)
- 巻号頁・発行日
- vol.19, no.3, pp.139-152, 2021 (Released:2021-06-10)
- 参考文献数
- 54
- 被引用文献数
- 1
In full-scale sewage treatment plants, long-term and high-frequency monitoring is required to mitigate nitrous oxide (N2O) emissions. In this study, the profile of the dissolved N2O concentration in a full-scale oxidation ditch reactor was investigated to determine the variation of the N2O emission factor. It was found that the concentration of dissolved N2O depended on microbial activity, which is affected by water temperature, dissolved oxygen concentration, and the dimensional relationship between the rotator and the inflow point. In the reactor, higher transcription levels of amoA mRNA and lower transcription levels of clade II type nosZ mRNA may be associated with N2O production. The emission factor for removed dissolved inorganic nitrogen presented a mean value of 0.86% and a median of 0.19%. When N2O production was promoted, gasification from the water surface was the most significant emission source, accounting for 52% of the total N2O emitted, on average. The N2O emission factor was often lower than 0.01% during stable operation; however, this factor was subject to sudden increases caused by nitrite accumulation.