BIORESOURCE TECHNOLOGY
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2024
·
IF 9.7
Luhan Cai,Yubiao Lu,Haiguang Zhu,Binxin Liu,Xinyi Li,Tianbo Jia,Jianxin Wang,Xueting Wang,Peng Li
The synchronous bioelectricity generation and dissimilatory nitrate reduction to ammonium (DNRA) pathway in Klebsiella variicola C1 was investigated. The presence of bioelectricity facilitated cell growth on the anodic biofilms, consequently enhancing the nitrate removal efficiency decreasing total nitrogen levels and causing a negligible accumulation of NO 2 – in the supernatant. Genomic analysis revealed that K. variicola C1 possessed a complete DNRA pathway and largely annotated electron shuttles. The up-regulated expression of genes narG and nirB , encoding nitrite oxidoreductase and nitrite reductase respectively, was closely associated with increased extracellular electron transfer (EET). High-throughput sequencing analysis was employed to investigate the impact of bioelectricity on microbial community composition within cathodic biofilms. Results indicated that Halomonas , Marinobacter and Prolixibacteraceae were enriched at the cathode electrodes. In conclusion, the integration of a DNRA strain with MFC facilitated the efficient removal of wastewater containing high concentrations of NO 3 – and enabled the environmentally friendly recovery of NH 4 + .
研究领域:
环境生物学
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微生物学
✓ 已验证
DOI
高影响因子
npj Clean Water
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2021
·Vol. 4
·期 1
·1-11
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IF 9.378
Ahmad Hafiz Adeel,Guo Beibei,Zhuang Xuming,Zhao Yiyi,Ahmad Shakeel,Lee Taeho,Zhu Jiegao,Dong Yuliang,Ni Shou-Qing
The prolonged start-up time and low total nitrogen removal of anammox hinder its full-scale application. Herein, application of nano-zerovalent iron and low strength magnetic field in sole and in combination to abbreviate the start-up period and long-term process stability of anammox was carried out. The reactor’s anammox start-up with the only magnetic field (R3) was 34 days, saving 43.3% time compared with the control. The increase of nitrogen removal efficiency over the control was 43.7% during the start-up period. However, the reactor with the coupled treatment of nano-zerovalent iron and magnetic field (R4) was more stable with higher nitrogen removal efficiency (80%) at high nitrogen loading (5.28 kg/m 3 /d). Anammox gene copy number in R4 was highest after 180 days of culture, followed by nano-zerovalent iron (R2) and R3 reactor. The functional genes of denitrifying bacteria (nirK and nirS) were also identified in all reactors with higher copy numbers in R2, followed by R4 and R3. Furthermore, high throughput analysis showed that the Thauera performing partial denitrification, Ignavibacterium performing dissimilatory nitrate reduction to ammonium or nitrite were also present in all reactors, more abundant in R4, confirming that the higher nitrogen removal efficiency in R4 was attributed to the synergistic relationship of other nitrogenous genera with anammox. The higher abundance of PD and DNRA in the reactor with the coupled treatment of nano-zero valent iron and magnetic field, achieved in this research, opens the opportunity of complete nitrogen removal via synergistic partial-denitrification, anammox, and DNRA (SPDAD) process.
研究领域:
环境科学
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微生物学
✓ 已验证
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
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2023
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IF 9.8
Xiaofang Ma,Jun Shan,Yanchao Chai,Zhijun Wei,Chenglin Li,Ke Jin,Han Zhou,Xiaoyuan Yan,Rong Ji
Microplastics (MPs) are frequently detected emerging pollutants in soil that can endanger farmland ecosystems; however, little is known about their impacts on dissimilatory nitrate reduction processes in paddy soil . Here, using the 15 N-tracer and microbial molecular techniques, we investigated the effects of MPs (200–400 μm) made of polystyrene (PS), polyvinyl chloride (PVC), and polyethylene (PE) on denitrification, anaerobic ammonium oxidation (Anammox), and dissimilatory nitrate reduction to ammonium (DNRA) and the associated microbial community in a black paddy soil. All MPs increased the Anammox rate by 6.6 %–745 % and decreased the DNRA rate by 15.1 %–74.2 %, while MPs of PS and PE significantly increased the denitrification rate by 79.3 %–102.3 % and 34.8 %–62.1 %, respectively. The MPs promoted the partitioning of NO 3 − towards denitrification and Anammox while inhibiting DNRA, as suggested by the decreased relative contributions of DNRA from 24.1 % to 5.4 %–14.2 % following MPs amendment. This was attributed to the increased denitrification gene abundance and the enriched specific denitrifier taxa, as well as the decreased DNRA gene abundance. Our findings suggest that the stimulated denitrification and Anammox by MPs, accompanied by the suppression of DNRA, may lead to substantial nitrogen loss in paddy fields , underscoring the need to further evaluate the environmental behaviors of MPs in agricultural ecosystems.
研究领域:
环境科学
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土壤微生物学
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农业生态学
✓ 已验证
DOI
PubMed
高影响因子
ACS Sustainable Chemistry & Engineering
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2020
·
IF 7.632
Zhen Bi,Wenjing Zhang,Min Ni,Ge Song,Yong Huang
The anammox bacteria (AnAOB) have been suggested to perform dissimilatory Fe0/Fe2+-dependent nitrate reduction to ammonium (DNRA), with nitrite as intermediate. However, evidence at genetic and transcriptional levels for how AnAOB reduces nitrate is still lacking, making their roles in this process obscure and questionable. The short-term batch assays and long-term operation of bioreactor combined with 16S rDNA sequencing and transcription analysis were used for the first time to investigate the nitrate reduction pathway in anammox consortia. It is shown that AnAOB metabolically well grew with nitrate as the sole nitrogen source. They reduced nitrate to nitrite with highly expressed narG gene. However, the DNRA-enabling gene nrfA was not expressed by AnAOB. Abiotic reduction by Fe0/Fe2+ contributed to the nitrate and nitrite reduction to ammonium. The correlation analysis of microbial community structure and metabolic functions indicated that amino acid and carbohydrate transport and metabolism interactions in coexisting bacteria could facilitate the AnAOB growth with nitrate as the only nitrogen source. Our findings suggest that the contribution of enzymatic DNRA by AnAOB to the observed nitrate reduction has been probably overestimated in previous publications, and it should be questioned until the clear enzymatic mechanism responsible for nitrate reduction is identified.
研究领域:
微生物学
·
环境科学
·
生物技术
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）