Zhang Nan, Zhang Yiting, Bohu Tsing, Wu Shanghua, Bai Zhihui, Zhuang Xuliang
Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
Sino-Danish College, University of Chinese Academy of Sciences, Beijing 100049, China.
Microorganisms. 2022 Jan 21;10(2):235. doi: 10.3390/microorganisms10020235.
The discovery of heterotrophic nitrification-aerobic denitrification (HN-AD) microorganisms has opened a new window for wastewater treatment. The underlying mechanism of HN-AD, however, is not fully understood because of the phylogenetic diversity of HN-AD microbes. The isolation and characterization of new HN-AD microorganisms are encouraging for furthering the understanding of this process. In this study, we found an isolate W30 from a historically polluted river in China through an HN-AD microbes screening process, which we identified as sp. A potential HN-AD pathway for W30 was proposed based on N conversion analyses and the successful amplification of the entire denitrification gene series. The isolate exhibited high efficiency of aerobic inorganic nitrogen transformation, which accounted for 97.11% of NH-N, 100% of NO-N, and 99.98% of NO-N removal with a maximum linear rate of 10.21 mg/L/h, 10.46 mg/L/h, and 10.77 mg/L/h, respectively. Assimilation rather than denitrification was the main mechanism for the environmental nitrogen depletion mediated by W30. The effect of environmental constraints on aerobic NO-N removal were characterized, following a membrane bioreactor effluent test under an oxic condition. Compared to known Alphaproteobacterial HN-AD microbes, we showed that sp. W30 could deplete nitrogen with no NO-N or NO-N accumulation in the HN-AD process. Therefore, the application of sp. W30 has the potential for developing a felicitous HN-AD technology to treat N-laden wastewater at the full-scale level.
异养硝化-好氧反硝化（HN-AD）微生物的发现为废水处理打开了一扇新窗口。然而，由于HN-AD微生物的系统发育多样性，HN-AD的潜在机制尚未完全明确。新的HN-AD微生物的分离和鉴定有助于进一步了解这一过程。在本研究中，我们通过HN-AD微生物筛选过程从中国一条历史污染河流中分离出一株菌株W30，经鉴定为 sp. 基于氮转化分析和整个反硝化基因系列的成功扩增，提出了W30可能的HN-AD途径。该菌株表现出高效的好氧无机氮转化能力，对NH-N、NO-N和NO-N的去除率分别为97.11%、100%和99.98%，最大线性去除速率分别为10.21 mg/L/h、10.46 mg/L/h和10.77 mg/L/h。同化作用而非反硝化作用是W30介导环境氮消耗的主要机制。在好氧条件下进行膜生物反应器出水测试，表征了环境限制对好氧NO-N去除的影响。与已知的α-变形菌纲HN-AD微生物相比，我们发现 sp. W30在HN-AD过程中能够实现氮的去除且无NO-N或NO-N积累。因此， sp. W30的应用具有开发合适的HN-AD技术以大规模处理含氮废水的潜力。
