School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, 510275, China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-sen University), Guangzhou, 510275, China.
School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, 510275, China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-sen University), Guangzhou, 510275, China.
Water Res. 2019 Sep 1;160:1-9. doi: 10.1016/j.watres.2019.05.021. Epub 2019 May 7.
The influence of diel temperature variations (DTVs) on nitrogen removal and bacterial communities was investigated in two parallel anammox reactors (i.e., control and DTV reactors). The control reactor was operated at a constant temperature of 30 °C, whereas the DTV reactor was operated in a temperature fluctuation mode with a cycle of 12/12 h of high/low temperatures. Nine water temperature variations for the day/night periods were set from 30/30 °C (i.e., Δ0 °C) to 38/22 °C (i.e., Δ16 °C). An increase in DTVs from Δ8 °C (34/26 °C) to Δ16 °C (38/22 °C) caused a significant decline in reactor performance and a shift in bacterial diversity. Compared to the control reactor, for instance, nitrogen removal efficiency decreased (P < 0.05) when temperature fluctuations exceeded Δ8 °C in the DTV reactor with a decreasing ΔNO/ΔNH ratio (from 0.21 ± 0.15 to 0.16 ± 0.04). The results of 16S rRNA gene sequencing showed that the initial disturbance of temperature variations led to increased levels of bacterial diversity (i.e., alpha diversity) and decreased community levels of anammox consortia whereas they slightly recovered at the end of each DTV phase. Notably, Candidatus Jettenia was more sensitive to strong water temperature fluctuations, with the lower relative abundance at Δ14 °C (17.11 ± 5.01%) and Δ16 °C (17.83 ± 7.22%) than at Δ4 °C (39.82 ± 0.01%). In contrast, Ca. Brocadia and Ca. Kuenenia had higher relative abundance at Δ14 °C (i.e., 0.24 ± 0.07% and 0.09 ± 0.02%, respectively) and Δ16 °C (i.e., 0.28 ± 0.05% and 0.12 ± 0.03%, respectively) compared to that at Δ4 °C (i.e., 0.15 ± 0.04% and 0.04 ± 0.01%, respectively). Nitrifiers (i.e., unidentified_Nitrospiraceae and Nitrosomonas) and denitrifiers (i.e., Denitratisoma) were also capable of tolerating high temperature perturbations. Overall this study furthers our knowledge of responses of the microbial ecology of anammox bacteria to DTVs in anammox processes, which could aid us in optimizing anammox-related wastewater treatment systems and in understanding the nitrogen cycles of natural ecosystems.
本研究在两个平行的厌氧氨氧化反应器（即对照和温度波动反应器）中考察了日温变化（DTV）对氮去除和细菌群落的影响。对照反应器在 30°C 的恒温下运行，而温度波动反应器则在 12/12 h 的高温/低温循环中运行。设定了 9 种日/夜温度变化，范围从 30/30°C（即 Δ0°C）到 38/22°C（即 Δ16°C）。与对照反应器相比，当 DTV 从 Δ8°C（34/26°C）增加到 Δ16°C（38/22°C）时，反应器性能显著下降，细菌多样性发生变化。例如，当 DTV 反应器中的温度波动超过 Δ8°C 时，与对照反应器相比，氮去除效率（P<0.05）下降，ΔNO/ΔNH 比值降低（从 0.21±0.15 降至 0.16±0.04）。16S rRNA 基因测序结果表明，温度波动的初始干扰导致细菌多样性（即α多样性）增加，厌氧氨氧化菌群落水平降低，但在每个 DTV 阶段结束时略有恢复。值得注意的是，Candidatus Jettenia 对强水温波动更为敏感，在 Δ14°C（17.11±5.01%）和 Δ16°C（17.83±7.22%）时的相对丰度低于 Δ4°C（39.82±0.01%）。相比之下，Ca. Brocadia 和 Ca. Kuenenia 在 Δ14°C（分别为 0.24±0.07%和 0.09±0.02%）和 Δ16°C（分别为 0.28±0.05%和 0.12±0.03%）时的相对丰度高于 Δ4°C（分别为 0.15±0.04%和 0.04±0.01%）。亚硝化菌（即未鉴定的_Nitrospiraceae 和 Nitrosomonas）和反硝化菌（即 Denitratisoma）也能耐受高温扰动。总体而言，本研究增进了我们对厌氧氨氧化菌微生物生态学对厌氧氨氧化过程中 DTV 响应的认识，这有助于我们优化与厌氧氨氧化相关的废水处理系统，并理解自然生态系统中的氮循环。
