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Zhu X, Lin F, Sun J, Li X, Zhu G, Lu Y, Sun L, Wang H. Effects of Weak Electric Fields on the Denitrification Performance of Pseudomonas stutzeri: Insights into Enzymes and Metabolic Pathways. Microorganisms 2024; 12:1218. [PMID: 38930600 PMCID: PMC11205929 DOI: 10.3390/microorganisms12061218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 06/07/2024] [Accepted: 06/12/2024] [Indexed: 06/28/2024] Open
Abstract
Enhanced denitrification has been reported under weak electric fields. However, it is difficult to investigate the mechanism of enhanced denitrification due to the complex interspecific interactions of mixed-culture systems. In this study, Pseudomonas stutzeri, capable of denitrification under anaerobic conditions, was selected for treating low COD/N (2.0, ratio between concentration of chemical oxygen demand and NO3--N) artificial wastewater under constant external voltages of 0.2, 0.4, and 0.6 V. The results revealed that P. stutzeri exhibited the highest efficiency in nitrate reduction at 0.2 V. Moreover, the maximum nitrate removal rate was 15.96 mg/(L·h) among the closed-circuit groups, 19.39% higher than that under the open-circuit group. Additionally, a notable reduction in nitrite accumulation was observed under weak electric fields. Enzyme activity analysis showed that the nitrate reductase activities were significantly increased among the closed-circuit groups, while nitrite reductase activities were inhibited. Transcriptomic analysis indicated that amino acid metabolism, carbohydrate metabolism, and energy metabolism were increased, enhancing the resistance of P. stutzeri to environmental stress and the efficiency of carbon source utilization for denitrification. The current study examined the impacts of weak electric fields on enzyme activities and microbial metabolic pathways and offers valuable insights into the mechanism by which denitrification is enhanced by weak electric fields.
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Affiliation(s)
- Xuyan Zhu
- School of Energy and Environment, Southeast University, Nanjing 210096, China; (X.Z.); (F.L.); (J.S.); (X.L.); (Y.L.); (L.S.)
| | - Feng Lin
- School of Energy and Environment, Southeast University, Nanjing 210096, China; (X.Z.); (F.L.); (J.S.); (X.L.); (Y.L.); (L.S.)
| | - Ji Sun
- School of Energy and Environment, Southeast University, Nanjing 210096, China; (X.Z.); (F.L.); (J.S.); (X.L.); (Y.L.); (L.S.)
| | - Xin Li
- School of Energy and Environment, Southeast University, Nanjing 210096, China; (X.Z.); (F.L.); (J.S.); (X.L.); (Y.L.); (L.S.)
| | - Guangcan Zhu
- School of Energy and Environment, Southeast University, Nanjing 210096, China; (X.Z.); (F.L.); (J.S.); (X.L.); (Y.L.); (L.S.)
| | - Yongze Lu
- School of Energy and Environment, Southeast University, Nanjing 210096, China; (X.Z.); (F.L.); (J.S.); (X.L.); (Y.L.); (L.S.)
| | - Liwei Sun
- School of Energy and Environment, Southeast University, Nanjing 210096, China; (X.Z.); (F.L.); (J.S.); (X.L.); (Y.L.); (L.S.)
| | - Hongyang Wang
- Chinese Research Academy of Environmental Sciences, Beijing 100012, China
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Liang H, Jia Y, Khanal SK, Huang D, Sun L, Lu H. Electrochemical-coupled sulfur-driven autotrophic denitrification for nitrogen removal from raw landfill leachate: Evaluation of performance and mechanisms. WATER RESEARCH 2024; 256:121592. [PMID: 38626614 DOI: 10.1016/j.watres.2024.121592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Revised: 04/03/2024] [Accepted: 04/08/2024] [Indexed: 04/18/2024]
Abstract
The cost-effective and environment-friendly sulfur-driven autotrophic denitrification (SdAD) process has drawn significant attention for advanced nitrogen removal from low carbon-to-nitrogen (C/N) ratio wastewater in recent years. However, achieving efficient nitrogen removal and maintaining system stability of SdAD process in treating low C/N landfill leachate treatment have been a major challenge. In this study, a novel electrochemical-coupled sulfur-driven autotrophic denitrification (ESdAD) system was developed and compared with SdAD system through a long-term continuous study. Superior nitrogen removal performance (removal efficiency of 89.1 ± 2.5 %) was achieved in ESdAD system compared to SdAD process when treating raw landfill leachate (influent total nitrogen (TN) concentration of 241.7 ± 36.3 mg-N/L), and the effluent TN concentration of ESdAD bioreactor was as low as 24.8 ± 5.1 mg-N/L, which meets the discharge standard of China (< 40 mg N/L). Moreover, less sulfate production rate (1.3 ± 0.2 mg SO42--S/mgNOx--N vs 1.7 ± 0.2 mg SO42--S/mgNOx--N) and excellent pH modulation (pH of 6.9 ± 0.2 vs 5.8 ± 0.4) were also achieved in the ESdAD system compared to SdAD system. The improvement of ESdAD system performance was contributed to coexistence and interaction of heterotrophic bacteria (e.g., Rhodanobacter, Thermomonas, etc.), sulfur autotrophic bacteria (e.g., Thiobacillus, Sulfurimonas, Ignavibacterium etc.) and hydrogen autotrophic bacteria (e.g., Thauera, Comamonas, etc.) under current stimulation. In addition, microbial nitrogen metabolic activity, including functional enzyme (e.g., Nar and Nir) activities and electron transfer capacity of extracellular polymeric substances (EPS) and cytochrome c (Cyt-C), were also enhanced during current stimulation, which facilitated the nitrogen removal and maintained system stability. These findings suggested that ESdAD is an effective and eco-friendly process for advanced nitrogen removal for low C/N wastewater.
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Affiliation(s)
- Huiyu Liang
- School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-Sen University), Guangzhou, PR China
| | - Yanyan Jia
- School of Ecology, Sun Yat-Sen University, Shenzhen, PR China
| | - Samir Kumar Khanal
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, USA
| | - Dongqi Huang
- School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-Sen University), Guangzhou, PR China
| | - Lianpeng Sun
- School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-Sen University), Guangzhou, PR China
| | - Hui Lu
- School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-Sen University), Guangzhou, PR China.
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Yuan S, Zhong Q, Zhang H, Zhu W, Wang W, Zhang S. Deciphering the influencing mechanism of hydraulic retention time on purification performance of a mixotrophic system from the perspective of reaction kinetics. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:12933-12947. [PMID: 38236564 DOI: 10.1007/s11356-023-31305-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 11/26/2023] [Indexed: 01/19/2024]
Abstract
At present, eutrophication is increasingly serious, so it is necessary to effectively reduce nitrogen and phosphorus in water bodies. In this study, a pyrite/polycaprolactone-based mixotrophic denitrification (PPMD) system using pyrite and polycaprolactone (PCL) as electron donors was developed and compared with pyrite-based autotrophic denitrification (PAD) system and PCL-based heterotrophic denitrification (PHD) system through continuous flow experiment. The removal efficiency of NO3--N (NRE) and PO43--P (PRE) and the contribution proportion of PAD in the PPMD system were significantly increased by prolonging hydraulic retention time (HRT, from 1 to 48 h). When HRT was equal to 24 h, the PPMD system conformed to the zero-order kinetic model, so NRE and PRE were mainly limited by the PAD process. When HRT was equal to 48 h, the PPMD system met the first-order kinetic model with NRE and PRE reaching 98.9 ± 1.1% and 91.8 ± 4.5%, respectively. When HRT = 48 h, the NRE and PRE by PAD system were 82.7 ± 9.1% and 88.5 ± 4.7%, respectively, but the effluent SO42- concentration was as high as 152.1 ± 13.7 mg/L (the influent SO42- concentration was 49.2 ± 3.3 mg/L); the NRE by PHD system was 98.5 ± 1.7%, but the PO43--P could not be removed ideally. The concentrations of NO3--N, total nitrogen, PO43--P, and SO42- in the PPMD system also showed distinct changes along the reactor column. In addition, the microbial diversity analysis showed that prolonging HRT (from 24 to 48 h) increased the abundance of autotrophic denitrifying microorganisms in the PPMD system, ultimately increasing the contribution proportion of PAD.
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Affiliation(s)
- Sicheng Yuan
- School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, 430070, People's Republic of China
| | - Qingbo Zhong
- School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, 430070, People's Republic of China
| | - Hongjun Zhang
- School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, 430070, People's Republic of China
| | - Wentao Zhu
- School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, 430070, People's Republic of China
| | - Weibo Wang
- CAS Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, People's Republic of China
| | - Shiyang Zhang
- School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, 430070, People's Republic of China.
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Yuan S, Zhong Q, Zhang H, Zhu W, Wang W, Li M, Tang X, Zhang S. The enrichment of more functional microbes induced by the increasing hydraulic retention time accounts for the increment of autotrophic denitrification performance. ENVIRONMENTAL RESEARCH 2023; 236:116848. [PMID: 37558114 DOI: 10.1016/j.envres.2023.116848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 07/27/2023] [Accepted: 08/06/2023] [Indexed: 08/11/2023]
Abstract
With pyrite (FeS2) and polycaprolactone (PCL) as electron donors, three denitrification systems, namely FeS2-based autotrophic denitrification (PAD) system, PCL-supported heterotrophic denitrification (PHD) system and split-mixotrophic denitrification (PPMD) system, were constructed and operated under varying hydraulic retention times (HRT, 1-48 h). Compared with PAD or PHD, the PPMD system could achieve higher removals of NO3--N and PO43--P, and the effluent SO42- concentration was greatly reduced to 7.28 mg/L. Similarly, the abundance of the dominant genera involved in the PAD (Thiobacillus, Sulfurimonas, and Ferritrophicum, etc.) or PHD (Syntrophomonas, Desulfomicrobium, and Desulfovibrio, etc.) process all increased in the PPMD system. Gene prediction completed by PICRUSt2 showed that the abundance of the functional genes involved in denitrification and sulfur oxidation all increased with the increase of HRT. This also accounted for the increased contribution of autotrophic denitrification to total nitrogen removal in the PPMD system. In addition, the analysis of metabolic pathways disclosed the specific conversion mechanisms of nitrogen and sulfur inside the reactor.
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Affiliation(s)
- Sicheng Yuan
- School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, 430070, PR China
| | - Qingbo Zhong
- School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, 430070, PR China
| | - Hongjun Zhang
- School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, 430070, PR China
| | - Wentao Zhu
- School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, 430070, PR China
| | - Weibo Wang
- CAS Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, PR China
| | - Meng Li
- School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, 430070, PR China
| | - Xinhua Tang
- School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, 430070, PR China
| | - Shiyang Zhang
- School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, 430070, PR China.
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Liu Y, Song X, Wang Y, Hou X, Cao X, Wang Y. Manganese-mediated ammonium removal by a bacterial consortium from wastewater: Experimental proof and biochemical mechanisms. BIORESOURCE TECHNOLOGY 2023:129353. [PMID: 37336457 DOI: 10.1016/j.biortech.2023.129353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 06/08/2023] [Accepted: 06/16/2023] [Indexed: 06/21/2023]
Abstract
Manganese-redox-mediated nitrogen transformation is promising for ammonium wastewater treatment. However, due to the limited contact between insoluble Mn and the microbe, extracellular electron transfer (EET) inefficiencies become a technical bottleneck in the technical practical application. To overcome this obstacle, humic acid (HA) was introduced to synthesize manganese-humic acid complex (Mn-HA) to increase Mn solubility. The TIN (Total Inorganic Nitrogen) removal rate constant k was 3.18, 1.08, 3.56, 1.13 and 1.05 times higher than CK (Control group) at 10, 15, 20, 40 and 60 mg/L influent nitrate in the MH group, respectively. Mn-HA was inferred to stimulated the nitrogen removal by providing more reaction active sites, bridging Mn-O bonds to transfer electrons and playing a redox role in the respiratory chain. A Mnammox-NDMO (manganese oxide reduction-coupled ammonium oxidation - nitrate/nitrite- dependent manganese oxidation) bacteria consortium was enriched in MH group, containing Mnammox bacteria Geothrix, Geobacter and NDMO bacteria Pseudomonas and Bacillus.
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Affiliation(s)
- Yingying Liu
- College of Environmental Science and Engineering, Donghua University, State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, Shanghai 201620, China.
| | - Xinshan Song
- College of Environmental Science and Engineering, Donghua University, State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, Shanghai 201620, China.
| | - Yifei Wang
- College of Environmental Science and Engineering, Donghua University, State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, Shanghai 201620, China.
| | - Xiaoxiao Hou
- College of Environmental Science and Engineering, Donghua University, State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, Shanghai 201620, China.
| | - Xin Cao
- College of Environmental Science and Engineering, Donghua University, State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, Shanghai 201620, China
| | - Yuhui Wang
- College of Environmental Science and Engineering, Donghua University, State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, Shanghai 201620, China
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