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Sun A, Liu X, Zhang S, Yang Q, Huang S, Zhang N. Enhancing Nitrogen Removal Efficiency and Anammox Metabolism in Microbial Electrolysis Cell Coupled Anammox Through Different Voltage Application. BIORESOURCE TECHNOLOGY 2023:129283. [PMID: 37277003 DOI: 10.1016/j.biortech.2023.129283] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 05/30/2023] [Accepted: 06/01/2023] [Indexed: 06/07/2023]
Abstract
The slow growth and difficulty in cultivating anammox bacteria limit the rapid start-up of anammox process and effective microbial enrichment. In this study, microbial electrolysis cell (MEC) was coupled with anammox to investigate the effects of different applying voltage methods on substrate removal efficiency and rates, microbial community structure, anammox metabolism and metabolic pathways. The results showed that applying voltage not only improved NH4+-N removal efficiency and removal rates, but also promoted electron transfer efficiency, key enzyme activity and extracellular polymeric substances (EPS) secretion in the systems. Step-up voltage was more conducive to the growth of Candidatus_Kuenenia in the cathode, which promoted the rapid start-up of anammox and treating wastewater with low ammonia concentration. The main metabolic pathway in step-up voltage operation was hydrazine to nitrogen, while in constant voltage operation was hydroxylamine oxidation pathway. These findings provide a new insight into the enhancement and operation of anammox system.
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Affiliation(s)
- Anran Sun
- Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Beijing University of Technology, Beijing 100124, China
| | - Xiuhong Liu
- Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Beijing University of Technology, Beijing 100124, China.
| | - Shiyong Zhang
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing 100124, China
| | - Qing Yang
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing 100124, China
| | - Songqing Huang
- Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Beijing University of Technology, Beijing 100124, China
| | - Nan Zhang
- Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Beijing University of Technology, Beijing 100124, China
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Wu MR, Miao LL, Liu Y, Qian XX, Hou TT, Ai GM, Yu L, Ma L, Gao XY, Qin YL, Zhu HZ, Du L, Li SY, Tian CL, Li DF, Liu ZP, Liu SJ. Identification and characterization of a novel hydroxylamine oxidase, DnfA, that catalyzes the oxidation of hydroxylamine to N 2. J Biol Chem 2022; 298:102372. [PMID: 35970391 PMCID: PMC9478400 DOI: 10.1016/j.jbc.2022.102372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 08/09/2022] [Accepted: 08/10/2022] [Indexed: 11/30/2022] Open
Abstract
Nitrogen (N2) gas in the atmosphere is partially replenished by microbial denitrification of ammonia. Recent study has shown that Alcaligenes ammonioxydans oxidizes ammonia to dinitrogen via a process featuring the intermediate hydroxylamine, termed “Dirammox” (direct ammonia oxidation). However, the unique biochemistry of this process remains unknown. Here, we report an enzyme involved in Dirammox that catalyzes the conversion of hydroxylamine to N2. We tested previously annotated proteins involved in redox reactions, DnfA, DnfB, and DnfC, to determine their ability to catalyze the oxidation of ammonia or hydroxylamine. Our results showed that none of these proteins bound to ammonia or catalyzed its oxidation; however, we did find DnfA bound to hydroxylamine. Further experiments demonstrated that, in the presence of NADH and FAD, DnfA catalyzed the conversion of 15N-labeled hydroxylamine to 15N2. This conversion did not happen under oxygen (O2)-free conditions. Thus, we concluded that DnfA encodes a hydroxylamine oxidase. We demonstrate that DnfA is not homologous to any known hydroxylamine oxidoreductases and contains a diiron center, which was shown to be involved in catalysis via electron paramagnetic resonance experiments. Furthermore, enzyme kinetics of DnfA were assayed, revealing a Km of 92.9 ± 3.0 μM for hydroxylamine and a kcat of 0.028 ± 0.001 s−1. Finally, we show that DnfA was localized in the cytoplasm and periplasm as well as in tubular membrane invaginations in HO-1 cells. To the best of our knowledge, we conclude that DnfA is the first enzyme discovered that catalyzes oxidation of hydroxylamine to N2.
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Affiliation(s)
- Meng-Ru Wu
- State Key Laboratory of Microbial Resources and Environmental Microbiology Research Center, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, No.19(A) Yuquan Road, Shijingshan District, Beijing, China 100049
| | - Li-Li Miao
- State Key Laboratory of Microbial Resources and Environmental Microbiology Research Center, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Ying Liu
- State Key Laboratory of Microbial Resources and Environmental Microbiology Research Center, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Xin-Xin Qian
- State Key Laboratory of Microbial Resources and Environmental Microbiology Research Center, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Ting-Ting Hou
- State Key Laboratory of Microbial Resources and Environmental Microbiology Research Center, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, No.19(A) Yuquan Road, Shijingshan District, Beijing, China 100049
| | - Guo-Min Ai
- State Key Laboratory of Microbial Resources and Environmental Microbiology Research Center, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Lu Yu
- High Magnetic Field Laboratory, Chinese Academy of Sciences, 230031, Hefei, China
| | - Lan Ma
- State Key Laboratory of Microbial Resources and Environmental Microbiology Research Center, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, No.19(A) Yuquan Road, Shijingshan District, Beijing, China 100049
| | - Xi-Yan Gao
- State Key Laboratory of Microbial Resources and Environmental Microbiology Research Center, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, No.19(A) Yuquan Road, Shijingshan District, Beijing, China 100049
| | - Ya-Ling Qin
- State Key Laboratory of Microbial Resources and Environmental Microbiology Research Center, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, No.19(A) Yuquan Road, Shijingshan District, Beijing, China 100049
| | - Hai-Zhen Zhu
- State Key Laboratory of Microbial Resources and Environmental Microbiology Research Center, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Lei Du
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266273, China
| | - Sheng-Ying Li
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266273, China
| | - Chang-Lin Tian
- High Magnetic Field Laboratory, Chinese Academy of Sciences, 230031, Hefei, China; The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, and Center for BioAnalytical Chemistry, Hefei National Laboratory of Physical Science at Microscale, University of Science and Technology of China, 230026, Hefei, Anhui, China
| | - De-Feng Li
- State Key Laboratory of Microbial Resources and Environmental Microbiology Research Center, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, No.19(A) Yuquan Road, Shijingshan District, Beijing, China 100049.
| | - Zhi-Pei Liu
- State Key Laboratory of Microbial Resources and Environmental Microbiology Research Center, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, No.19(A) Yuquan Road, Shijingshan District, Beijing, China 100049.
| | - Shuang-Jiang Liu
- State Key Laboratory of Microbial Resources and Environmental Microbiology Research Center, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, No.19(A) Yuquan Road, Shijingshan District, Beijing, China 100049; State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266273, China.
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Shi F, Liu Z, Li J, Gao H, Qin S, Guo J. Alterations in microbial community during the remediation of a black-odorous stream by acclimated composite microorganisms. J Environ Sci (China) 2022; 118:181-193. [PMID: 35305767 DOI: 10.1016/j.jes.2021.12.034] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Revised: 12/19/2021] [Accepted: 12/19/2021] [Indexed: 06/14/2023]
Abstract
Microbial application is an efficient, economical, and ecofriendly method for remediating black-odorous rivers. In this study, the field treatment effect and microbial community changes were monitored during remediation by the acclimated complex microorganisms of a typical black-odorous stream. After the treatment, the total phosphorus and ammonia contents decreased by 74.0% and 76.3% and the concentrations of dissolved oxygen increased from 1.65 to 4.90 mg/L, indicating the effectiveness of the acclimated composite microorganisms. The proportion of Bacteroidetes decreased significantly by 48.1% and that of Firmicutes increased by 2.23% on average, and the microbial diversity index first increased and then tended to be uniform. Redundancy analysis demonstrated that the pH, dissolved oxygen, and oxidation-reduction potential together determined the composition of the microbial communities (p < 0.05). These findings showed that the acclimated composite microorganisms can effectively remediate the black odor.
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Affiliation(s)
- Feng Shi
- Key Lab of Coastal Biology and Biological Resource Conservation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China; College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Zongli Liu
- Qingdao HOOH Environmental Protection Technology Co. Ltd. Qingdao 266073, China
| | - Jialin Li
- Key Lab of Coastal Biology and Biological Resource Conservation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China.
| | - Huiwang Gao
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Song Qin
- Key Lab of Coastal Biology and Biological Resource Conservation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China
| | - Jingjing Guo
- Qingdao HOOH Environmental Protection Technology Co. Ltd. Qingdao 266073, China
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Hozuki T, Ohtsuka T, Arai K, Yoshimatsu K, Tanaka S, Fujiwara T. Effect of salinity on hydroxylamine oxidation in a marine ammonia-oxidizing gammaproteobacterium, Nitrosococcus oceani strain NS58: molecular and catalytic properties of tetraheme cytochrome c-554. Microbes Environ 2011; 25:95-102. [PMID: 21576859 DOI: 10.1264/jsme2.me09154] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Tetraheme cytochrome c-554 is a physiological electron acceptor of hydroxylamine oxidoreductase (HAO), a core enzyme of ammonia oxidation in chemoautotrophic nitrifiers. Here we report the purification of cytochrome c-554 from Nitrosococcus oceani strain NS58, a marine gammaproteobacterial ammonia-oxidizing bacterium. The NS58 cytochrome is a 25 kDa-protein having four hemes c. The absorption spectrum of the cytochrome showed peaks at 420 nm, 523 nm, and 554 nm, with shoulders at around 430 nm and 580 nm in the reduced state. In contrast to the highly basic counterpart from the betaproteobacterium Nitrosomonas europaea, the NS58 cytochrome c-554 was an acidic protein whose isoelectric point was 4.6. HAO was also purified, and the reaction with the NS58 cytochrome was found to be salt-tolerant. Compared with the activity observed in a non-salt solution, 60% of the activity remained in a saline concentration comparable to that of seawater.
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Affiliation(s)
- Takeshi Hozuki
- Department of Biological Science, Graduate School of Science, Shizuoka University, 836 Oh-ya, Suruga-ku, Shizuoka 422–8529, Japan
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Zahn JA, Duncan C, DiSpirito AA. Oxidation of hydroxylamine by cytochrome P-460 of the obligate methylotroph Methylococcus capsulatus Bath. J Bacteriol 1994; 176:5879-87. [PMID: 7928947 PMCID: PMC196803 DOI: 10.1128/jb.176.19.5879-5887.1994] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
An enzyme capable of the oxidation of hydroxylamine to nitrite was isolated from the obligate methylotroph Methylococcus capsulatus Bath. The absorption spectra in cell extracts, electron paramagnetic resonance spectra, molecular weight, covalent attachment of heme group to polypeptide, and enzymatic activities suggest that the enzyme is similar to cytochrome P-460, a novel iron-containing protein previously observed only in Nitrosomonas europaea. The native and subunit molecular masses of the M. capsulatus Bath protein were 38,900 and 16,390 Da, respectively; the isoelectric point was 6.98. The enzyme has approximately one iron and one copper atom per subunit. The electron paramagnetic resonance spectrum of the protein showed evidence for a high-spin ferric heme. In contrast to the enzyme from N. europaea, a 13-nm blue shift in the soret band of the ferrocytochrome (463 nm in cell extracts to 450 nm in the final sample) occurred during purification. The amino acid composition and N-terminal amino acid sequence of the enzyme from M. capsulatus Bath was similar but not identical to those of cytochrome P-460 of N. europaea. In cell extracts, the identity of the biological electron acceptor is as yet unestablished. Cytochrome c-555 is able to accept electrons from cytochrome P-460, although the purified enzyme required phenazine methosulfate for maximum hydroxylamine oxidation activity (specific activity, 366 mol of O2 per s per mol of enzyme). Hydroxylamine oxidation rates were stimulated approximately 2-fold by 1 mM cyanide and 1.5-fold by 0.1 mM 8-hydroxyquinoline.
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Affiliation(s)
- J A Zahn
- Department of Microbiology, Immunology, and Preventive Medicine, Iowa State University, Ames 50011
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