The Experts below are selected from a list of 13332 Experts worldwide ranked by ideXlab platform
Yongzhen Peng - One of the best experts on this subject based on the ideXlab platform.
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An improved start-up strategy for mainstream Anammox process through inoculating ordinary nitrification sludge and a small amount of Anammox sludge.
Journal of hazardous materials, 2019Co-Authors: Miao Yuanyuan, Jianhua Zhang, Yongzhen Peng, Wang SimengAbstract:The difficulties in enriching Anammox bacteria and maintaining stable partial nitrification during start-up phase limit the application of mainstream Anammox process. In this study, the feasibility of starting up simultaneous partial nitrification, Anammox and denitrification (SNAD) reactor treating municipal wastewater by inoculating ordinary nitrification sludge (96.2%) and a small amount of Anammox sludge (3.8%) was investigated. A sequencing batch reactor with intermittent aeration was used for the SNAD process. The SNAD reactor was started up in 75 days with a nitrogen removal efficiency of 85.4% at ambient temperature. The nitrogen removal performance maintained stable despite the fluctuating inflow. Anammox bacterial activity exponentially increased although nitrite oxidizing bacteria (NOB) activity in seeding sludge was high. The enhanced ammonium oxidizing bacterial activity and partial denitrification provided sufficient nitrite for Anammox bacteria. Moreover, NOB was inhibited by intermittent aeration, Anammox bacteria had competitive advantage on nitrite. The improved particle size and settleability of activated sludge also favored the Anammox bacterial enrichment. This study provided an improved and easily-implemented start-up strategy for mainstream Anammox. The seeding sludge was easily obtained and the operation strategy was simple. These findings were meaningful to the engineering application of mainstream Anammox.
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Suspended sludge and biofilm shaped different Anammox communities in two pilot-scale one-stage Anammox reactors.
Bioresource technology, 2016Co-Authors: Zheng Bingyu, Liang Zhang, Anming Yang, Shujun Zhang, Jianhua Guo, Yongzhen PengAbstract:The abundance and diversity of Anammox bacteria was investigated in two pilot-scale integrated fixed-film activated sludge (IFAS) reactors treating high ammonium wastewater. Reactor A was inoculated with nitrifying sludge, while Reactor B was inoculated with suspended Anammox sludge with the dominant Anammox bacteria of Candidatus 'Kuenenia'. After 180days' operation, the predominate Anammox bacteria was Candidatus 'Brocadia' (65%) in the biofilm, while Candidatus 'Kuenenia' (86%) outcompeted with other Anammox bacteria in suspended sludge in Reactor A. Candidatus 'Kuenenia' were dominated in suspended sludge through the entire experiment in Reactor B. In contrast, the predominated species shifted from Candidatus 'Kuenenia' (89%) into Candidatus 'Brocadia' (66%) in the biofilm of Reactor B. This study indicated that Candidatus 'Brocadia' preferred to grow in the biofilm, while Candidatus 'Kuenenia' would dominant over other Anammox bacteria in the suspended sludge. Further studies are required to identify the internal factors affecting the distribution of Anammox bacteria.
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biological nitrogen removal from sewage via Anammox recent advances
Bioresource Technology, 2016Co-Authors: Shanyun Wang, Yongzhen Peng, Shenbin Cao, Yuanyuan Miao, Fangxu JiaAbstract:Biological nitrogen removal from sewage via Anammox is a promising and feasible technology to make sewage treatment energy-neutral or energy-positive. Good retention of Anammox bacteria is the premise of achieving sewage treatment via Anammox. Therefore the Anammox metabolism and its factors were critically reviewed so as to form biofilm/granules for retaining Anammox bacteria. A stable supply of nitrite for Anammox bacteria is a real bottleneck for applying Anammox in sewage treatment. Nitritation and partial-denitrification are two promising methods of offering nitrite. As such, the strategies for achieving nitritation in sewage treatment were summarized by reviewing the factors affecting nitrite oxidation bacteria growth. Meanwhile, the methods of achieving partial-denitrification have been developed through understanding the microorganisms related with nitrite accumulation and their factors. Furthermore, two cases of applying Anammox in the mainstream sewage treatment plants were documented.
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Distribution and influence factors of Anammox bacteria in sewage treatment systems
Sheng wu gong cheng xue bao = Chinese journal of biotechnology, 2014Co-Authors: Zheng Bingyu, Yongzhen Peng, Liang Zhang, Anming Yang, Shujun ZhangAbstract:Nitrogen removal techniques based on Anammox process are developing rapidly these years. The distribution and diversity of Anammox have become important research directions. A variety of Anammox have been detected till now, of which only Kuenenia and Brocadia are often detected in wastewater treatment systems. In addition, in a single niche there is only one type of Anammox bacteria. However, the distribution mechanism and transformation of Anammox bacteria in different niches are still ambiguous. Therefore, the distribution of Anammox in various conditions was summarized and analyzed in this article. And the key factors influencing the distribution of Anammox were concluded, including substrate concentration and the specific growth rate, sludge properties and microbial niche, the joint action and influence of multiple factors. The engineering significance research on the distribution and influencing factors of Anammox bacteria in the sewage system and proposed research prospects were expounded.
Guibing Zhu - One of the best experts on this subject based on the ideXlab platform.
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anaerobic ammonium oxidation in agricultural soils synthesis and prospective
Environmental Pollution, 2019Co-Authors: Sanan Nie, Guibing Zhu, Brajesh K Singh, Yong-guan ZhuAbstract:Denitrification is considered as the dominant nitrogen (N) removing pathway, however, anaerobic oxidation of ammonium (Anammox) also plays a significant part in N loss in agricultural ecosystems. Large N inputs into agricultural soils may stimulate the growth of Anammox bacteria, resulting in high activity and diversity of Anammox bacteria and subsequent more N loss. In some specific niches, like oxic-anoxic interface, three processes, nitrification, Anammox and denitrification couple with each other, and significant Anammox reaction could be observed. Soil parameters like pH, dissolved oxygen, salinity, oxidation-reduction potential (ORP), and substrate concentrations impact the Anammox process. Here we summarize the current knowledge on Anammox activity and contribution to N loss, abundance and diversity of Anammox bacteria, factors affecting Anammox, and the relationship between Anammox and other N loss pathways in agricultural soils. We propose that more investigations are required for (1) the role of Anammox to N loss with different agricultural management strategies; (2) microscale research on the coupling of nitrification-Anammox-denitrification, that might be a very complex process but ideal model for further studies responsible for N cycling in terrestrial ecosystems; and (3) new methods to estimate differential contributions of Anammox, codenitrification and denitrification in total N loss in agricultural ecosystems. New research will provide much needed information to quantify the contribution of Anammox in N loss from soils at landscape, ecosystem and global scales.
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Nitrogen loss by anaerobic ammonium oxidation in unconfined aquifer soils.
Scientific reports, 2017Co-Authors: Shanyun Wang, Mike S. M. Jetten, Dirk Radny, Shuangbing Huang, Linjie Zhuang, Siyan Zhao, Michael Berg, Guibing ZhuAbstract:Anaerobic ammonium oxidation (Anammox) is recognized as an important process for nitrogen cycling, yet little is known about its role in the subsurface biosphere. In this study, we investigated the presence, abundance, and role of Anammox bacteria in upland soil cores from Tianjin, China (20 m depth) and Basel, Switzerland (10 m depth), using isotope-tracing techniques, (q)PCR assays, and 16 S rRNA &hzsB gene clone libraries, along with nutrient profiles of soil core samples. Anammox in the phreatic (water-saturated) zone contributed to 37.5-67.6% of the N-loss (up to 0.675 gN m-2 d-1), with Anammox activities of 0.005-0.74 nmolN g-1 soil h-1, which were even higher than the denitrification rates. By contrast, no significant Anammox was measured in the vadose zone. Higher Anammox bacterial cell densities were observed (0.75-1.4 × 107 copies g-1 soil) in the phreatic zone, where ammonia-oxidizing bacteria (AOB) maybe the major source of nitrite for Anammox bacteria. The Anammox bacterial cells in soils of the vadose zone were all
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nitrogen loss by anaerobic ammonium oxidation in unconfined aquifer soils
Scientific Reports, 2017Co-Authors: Shanyun Wang, Mike S. M. Jetten, Dirk Radny, Shuangbing Huang, Linjie Zhuang, Siyan Zhao, Michael Berg, Guibing ZhuAbstract:Anaerobic ammonium oxidation (Anammox) is recognized as an important process for nitrogen cycling, yet little is known about its role in the subsurface biosphere. In this study, we investigated the presence, abundance, and role of Anammox bacteria in upland soil cores from Tianjin, China (20 m depth) and Basel, Switzerland (10 m depth), using isotope-tracing techniques, (q)PCR assays, and 16 S rRNA & hzsB gene clone libraries, along with nutrient profiles of soil core samples. Anammox in the phreatic (water-saturated) zone contributed to 37.5–67.6% of the N-loss (up to 0.675 gN m−2d−1), with Anammox activities of 0.005–0.74 nmolN g−1soil h−1, which were even higher than the denitrification rates. By contrast, no significant Anammox was measured in the vadose zone. Higher Anammox bacterial cell densities were observed (0.75–1.4 × 107copies g−1soil) in the phreatic zone, where ammonia-oxidizing bacteria (AOB) maybe the major source of nitrite for Anammox bacteria. The Anammox bacterial cells in soils of the vadose zone were all <103copies g−1soil. We suggest that the subsurface provides a favorable niche for Anammox bacteria whose contribution to N cycling and groundwater nitrate removal seems considerably larger than previously known.
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potential contribution of Anammox to nitrogen loss from paddy soils in southern china
Applied and Environmental Microbiology, 2015Co-Authors: Xiao-ru Yang, Guibing Zhu, Sanan Nie, Bosen Weng, Jack A Gilbert, Huaiying Yao, Yong-guan ZhuAbstract:The anaerobic oxidation of ammonium (Anammox) process has been observed in diverse terrestrial ecosystems, while the contribution of Anammox to N2 production in paddy soils is not well documented. In this study, the Anammox activity and the abundance and diversity of Anammox bacteria were investigated to assess the Anammox potential of 12 typical paddy soils collected in southern China. Anammox bacteria related to "Candidatus Brocadia" and "Candidatus Kuenenia" and two novel unidentified clusters were detected, with "Candidatus Brocadia" comprising 50% of the Anammox population. The prevalence of the Anammox was confirmed by the quantitative PCR results based on hydrazine synthase (hzsB) genes, which showed that the abundance ranged from 1.16 × 10(4) to 9.65 × 10(4) copies per gram of dry weight. The Anammox rates measured by the isotope-pairing technique ranged from 0.27 to 5.25 nmol N per gram of soil per hour in these paddy soils, which contributed 0.6 to 15% to soil N2 production. It is estimated that a total loss of 2.50 × 10(6) Mg N per year is linked to Anammox in the paddy fields in southern China, which implied that ca. 10% of the applied ammonia fertilizers is lost via the Anammox process. Anammox activity was significantly correlated with the abundance of hzsB genes, soil nitrate concentration, and C/N ratio. Additionally, ammonia concentration and pH were found to be significantly correlated with the Anammox bacterial structure.
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potential roles of anaerobic ammonium and methane oxidation in the nitrogen cycle of wetland ecosystems
Applied Microbiology and Biotechnology, 2010Co-Authors: Guibing Zhu, Mike S. M. Jetten, Peter Kuschk, Katharina F Ettwig, Chengqing YinAbstract:Anaerobic ammonium oxidation (Anammox) and anaerobic methane oxidation (ANME coupled to denitrification) with nitrite as electron acceptor are two of the most recent discoveries in the microbial nitrogen cycle. Currently the Anammox process has been relatively well investigated in a number of natural and man-made ecosystems, while ANME coupled to denitrification has only been observed in a limited number of freshwater ecosystems. The ubiquitous presence of Anammox bacteria in marine ecosystems has changed our knowledge of the global nitrogen cycle. Up to 50% of N(2) production in marine sediments and oxygen-depleted zones may be attributed to Anammox bacteria. However, there are only few indications of Anammox in natural and constructed freshwater wetlands. In this paper, the potential role of Anammox and denitrifying methanotrophic bacteria in natural and artificial wetlands is discussed in relation to global warming. The focus of the review is to explore and analyze if suitable environmental conditions exist for Anammox and denitrifying methanotrophic bacteria in nitrogen-rich freshwater wetlands.
Mike S. M. Jetten - One of the best experts on this subject based on the ideXlab platform.
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Nitrogen loss by anaerobic ammonium oxidation in unconfined aquifer soils.
Scientific reports, 2017Co-Authors: Shanyun Wang, Mike S. M. Jetten, Dirk Radny, Shuangbing Huang, Linjie Zhuang, Siyan Zhao, Michael Berg, Guibing ZhuAbstract:Anaerobic ammonium oxidation (Anammox) is recognized as an important process for nitrogen cycling, yet little is known about its role in the subsurface biosphere. In this study, we investigated the presence, abundance, and role of Anammox bacteria in upland soil cores from Tianjin, China (20 m depth) and Basel, Switzerland (10 m depth), using isotope-tracing techniques, (q)PCR assays, and 16 S rRNA &hzsB gene clone libraries, along with nutrient profiles of soil core samples. Anammox in the phreatic (water-saturated) zone contributed to 37.5-67.6% of the N-loss (up to 0.675 gN m-2 d-1), with Anammox activities of 0.005-0.74 nmolN g-1 soil h-1, which were even higher than the denitrification rates. By contrast, no significant Anammox was measured in the vadose zone. Higher Anammox bacterial cell densities were observed (0.75-1.4 × 107 copies g-1 soil) in the phreatic zone, where ammonia-oxidizing bacteria (AOB) maybe the major source of nitrite for Anammox bacteria. The Anammox bacterial cells in soils of the vadose zone were all
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nitrogen loss by anaerobic ammonium oxidation in unconfined aquifer soils
Scientific Reports, 2017Co-Authors: Shanyun Wang, Mike S. M. Jetten, Dirk Radny, Shuangbing Huang, Linjie Zhuang, Siyan Zhao, Michael Berg, Guibing ZhuAbstract:Anaerobic ammonium oxidation (Anammox) is recognized as an important process for nitrogen cycling, yet little is known about its role in the subsurface biosphere. In this study, we investigated the presence, abundance, and role of Anammox bacteria in upland soil cores from Tianjin, China (20 m depth) and Basel, Switzerland (10 m depth), using isotope-tracing techniques, (q)PCR assays, and 16 S rRNA & hzsB gene clone libraries, along with nutrient profiles of soil core samples. Anammox in the phreatic (water-saturated) zone contributed to 37.5–67.6% of the N-loss (up to 0.675 gN m−2d−1), with Anammox activities of 0.005–0.74 nmolN g−1soil h−1, which were even higher than the denitrification rates. By contrast, no significant Anammox was measured in the vadose zone. Higher Anammox bacterial cell densities were observed (0.75–1.4 × 107copies g−1soil) in the phreatic zone, where ammonia-oxidizing bacteria (AOB) maybe the major source of nitrite for Anammox bacteria. The Anammox bacterial cells in soils of the vadose zone were all <103copies g−1soil. We suggest that the subsurface provides a favorable niche for Anammox bacteria whose contribution to N cycling and groundwater nitrate removal seems considerably larger than previously known.
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hydrazine synthase a unique phylomarker with which to study the presence and biodiversity of Anammox bacteria
Applied and Environmental Microbiology, 2012Co-Authors: Harry R Harhangi, Boran Kartal, Mike S. M. Jetten, Mathilde Le Roy, Theo A Van Alen, Joost Groen, Susannah G Tringe, Zhexue Quan, Huub Op Den J M CampAbstract:Anaerobic ammonium-oxidizing (Anammox) bacteria play an important role in the biogeochemical cycling of nitrogen. They derive their energy for growth from the conversion of ammonium and nitrite into dinitrogen gas in the complete absence of oxygen. Several methods have been used to detect the presence and activity of Anammox bacteria in the environment, including 16S rRNA gene-based approaches. The use of the 16S rRNA gene to study biodiversity has the disadvantage that it is not directly related to the physiology of the target organism and that current primers do not completely capture the Anammox diversity. Here we report the development of PCR primer sets targeting a subunit of the hydrazine synthase (hzsA), which represents a unique phylogenetic marker for Anammox bacteria. The tested primers were able to retrieve hzsA gene sequences from Anammox enrichment cultures, full-scale Anammox wastewater treatment systems, and a variety of freshwater and marine environmental samples, covering all known Anammox genera.
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identification and quantification of Anammox bacteria in eight nitrogen removal reactors
Water Research, 2010Co-Authors: Ping Zheng, Chong-jian Tang, Mike S. M. Jetten, Jianwei Chen, Jia Yan, Erwin Van Der Biezen, Lei Zhang, Boran KartalAbstract:Abstract Various studies have revealed anaerobic ammonium oxidation (Anammox) as a very attractive alternative process suitable for nitrogen removal from wastewater. Here we investigated Anammox bacteria in eight different nitrogen removal reactors. The diversity and abundance of Anammox bacteria were determined by the 16S rRNA gene analysis, fluorescence in situ hybridization with specific probes and real-time quantitative PCR (qPCR). In these reactors, at least eight unique near full length Anammox 16S rRNA gene sequences were detected, which were distributed over two genera; Candidati Brocadia and Kuenenia . FISH results confirmed that only one Anammox bacterium dominated the community in each of the eight reactors investigated in this study. qPCR analysis revealed that Anammox bacteria were present in seven of the reactors in the order of 10 9 cells/ml and 10 7 cells/ml in reactor A1. The dominant and divergent Brocadia -like Anammox phylotype in one reactor represented a novel species for which we propose the name Candidatus Brocadia sinica . Taken together, these results indicated that a single seeding source could be used to seed Anammox reactors designed to treat different types of wastewater, which could lead to a faster start-up of bioreactors.
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potential roles of anaerobic ammonium and methane oxidation in the nitrogen cycle of wetland ecosystems
Applied Microbiology and Biotechnology, 2010Co-Authors: Guibing Zhu, Mike S. M. Jetten, Peter Kuschk, Katharina F Ettwig, Chengqing YinAbstract:Anaerobic ammonium oxidation (Anammox) and anaerobic methane oxidation (ANME coupled to denitrification) with nitrite as electron acceptor are two of the most recent discoveries in the microbial nitrogen cycle. Currently the Anammox process has been relatively well investigated in a number of natural and man-made ecosystems, while ANME coupled to denitrification has only been observed in a limited number of freshwater ecosystems. The ubiquitous presence of Anammox bacteria in marine ecosystems has changed our knowledge of the global nitrogen cycle. Up to 50% of N(2) production in marine sediments and oxygen-depleted zones may be attributed to Anammox bacteria. However, there are only few indications of Anammox in natural and constructed freshwater wetlands. In this paper, the potential role of Anammox and denitrifying methanotrophic bacteria in natural and artificial wetlands is discussed in relation to global warming. The focus of the review is to explore and analyze if suitable environmental conditions exist for Anammox and denitrifying methanotrophic bacteria in nitrogen-rich freshwater wetlands.
Shanyun Wang - One of the best experts on this subject based on the ideXlab platform.
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Nitrogen loss by anaerobic ammonium oxidation in unconfined aquifer soils.
Scientific reports, 2017Co-Authors: Shanyun Wang, Mike S. M. Jetten, Dirk Radny, Shuangbing Huang, Linjie Zhuang, Siyan Zhao, Michael Berg, Guibing ZhuAbstract:Anaerobic ammonium oxidation (Anammox) is recognized as an important process for nitrogen cycling, yet little is known about its role in the subsurface biosphere. In this study, we investigated the presence, abundance, and role of Anammox bacteria in upland soil cores from Tianjin, China (20 m depth) and Basel, Switzerland (10 m depth), using isotope-tracing techniques, (q)PCR assays, and 16 S rRNA &hzsB gene clone libraries, along with nutrient profiles of soil core samples. Anammox in the phreatic (water-saturated) zone contributed to 37.5-67.6% of the N-loss (up to 0.675 gN m-2 d-1), with Anammox activities of 0.005-0.74 nmolN g-1 soil h-1, which were even higher than the denitrification rates. By contrast, no significant Anammox was measured in the vadose zone. Higher Anammox bacterial cell densities were observed (0.75-1.4 × 107 copies g-1 soil) in the phreatic zone, where ammonia-oxidizing bacteria (AOB) maybe the major source of nitrite for Anammox bacteria. The Anammox bacterial cells in soils of the vadose zone were all
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nitrogen loss by anaerobic ammonium oxidation in unconfined aquifer soils
Scientific Reports, 2017Co-Authors: Shanyun Wang, Mike S. M. Jetten, Dirk Radny, Shuangbing Huang, Linjie Zhuang, Siyan Zhao, Michael Berg, Guibing ZhuAbstract:Anaerobic ammonium oxidation (Anammox) is recognized as an important process for nitrogen cycling, yet little is known about its role in the subsurface biosphere. In this study, we investigated the presence, abundance, and role of Anammox bacteria in upland soil cores from Tianjin, China (20 m depth) and Basel, Switzerland (10 m depth), using isotope-tracing techniques, (q)PCR assays, and 16 S rRNA & hzsB gene clone libraries, along with nutrient profiles of soil core samples. Anammox in the phreatic (water-saturated) zone contributed to 37.5–67.6% of the N-loss (up to 0.675 gN m−2d−1), with Anammox activities of 0.005–0.74 nmolN g−1soil h−1, which were even higher than the denitrification rates. By contrast, no significant Anammox was measured in the vadose zone. Higher Anammox bacterial cell densities were observed (0.75–1.4 × 107copies g−1soil) in the phreatic zone, where ammonia-oxidizing bacteria (AOB) maybe the major source of nitrite for Anammox bacteria. The Anammox bacterial cells in soils of the vadose zone were all <103copies g−1soil. We suggest that the subsurface provides a favorable niche for Anammox bacteria whose contribution to N cycling and groundwater nitrate removal seems considerably larger than previously known.
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biological nitrogen removal from sewage via Anammox recent advances
Bioresource Technology, 2016Co-Authors: Shanyun Wang, Yongzhen Peng, Shenbin Cao, Yuanyuan Miao, Fangxu JiaAbstract:Biological nitrogen removal from sewage via Anammox is a promising and feasible technology to make sewage treatment energy-neutral or energy-positive. Good retention of Anammox bacteria is the premise of achieving sewage treatment via Anammox. Therefore the Anammox metabolism and its factors were critically reviewed so as to form biofilm/granules for retaining Anammox bacteria. A stable supply of nitrite for Anammox bacteria is a real bottleneck for applying Anammox in sewage treatment. Nitritation and partial-denitrification are two promising methods of offering nitrite. As such, the strategies for achieving nitritation in sewage treatment were summarized by reviewing the factors affecting nitrite oxidation bacteria growth. Meanwhile, the methods of achieving partial-denitrification have been developed through understanding the microorganisms related with nitrite accumulation and their factors. Furthermore, two cases of applying Anammox in the mainstream sewage treatment plants were documented.
Yong-guan Zhu - One of the best experts on this subject based on the ideXlab platform.
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Earthworm gut: An overlooked niche for anaerobic ammonium oxidation in agricultural soil
The Science of the total environment, 2020Co-Authors: Xiao-ru Yang, Juan Wang, Guo-wei Zhou, Yu-sen Zhang, Simon Bo Lassen, Yong-guan ZhuAbstract:Abstract Soil fauna takes an active part in accelerating turnover of nutrients in terrestrial ecosystems. Anaerobic ammonium oxidation (Anammox) has been widely characterized, however, whether Anammox is active in earthworm gut and the effect of earthworm on Anammox in soil remain unknown. In this study, the activity, abundance and community of Anammox bacteria in earthworm guts and soils from microcosms were determined using a 15N-tracing technique, quantitative PCR, and Anammox bacterial 16S rRNA gene amplicon sequencing. Results showed that Anammox rates in guts ranged between 5.81 and 14.19 nmol N g−1 dw gut content h−1, which were significantly (P
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anaerobic ammonium oxidation in agricultural soils synthesis and prospective
Environmental Pollution, 2019Co-Authors: Sanan Nie, Guibing Zhu, Brajesh K Singh, Yong-guan ZhuAbstract:Denitrification is considered as the dominant nitrogen (N) removing pathway, however, anaerobic oxidation of ammonium (Anammox) also plays a significant part in N loss in agricultural ecosystems. Large N inputs into agricultural soils may stimulate the growth of Anammox bacteria, resulting in high activity and diversity of Anammox bacteria and subsequent more N loss. In some specific niches, like oxic-anoxic interface, three processes, nitrification, Anammox and denitrification couple with each other, and significant Anammox reaction could be observed. Soil parameters like pH, dissolved oxygen, salinity, oxidation-reduction potential (ORP), and substrate concentrations impact the Anammox process. Here we summarize the current knowledge on Anammox activity and contribution to N loss, abundance and diversity of Anammox bacteria, factors affecting Anammox, and the relationship between Anammox and other N loss pathways in agricultural soils. We propose that more investigations are required for (1) the role of Anammox to N loss with different agricultural management strategies; (2) microscale research on the coupling of nitrification-Anammox-denitrification, that might be a very complex process but ideal model for further studies responsible for N cycling in terrestrial ecosystems; and (3) new methods to estimate differential contributions of Anammox, codenitrification and denitrification in total N loss in agricultural ecosystems. New research will provide much needed information to quantify the contribution of Anammox in N loss from soils at landscape, ecosystem and global scales.
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the phenological stage of rice growth determines anaerobic ammonium oxidation activity in rhizosphere soil
Soil Biology & Biochemistry, 2016Co-Authors: Xiao-ru Yang, Sanan Nie, Bosen Weng, Jack A Gilbert, Yong-guan ZhuAbstract:Abstract Anaerobic oxidation of ammonium (Anammox) plays an important role in nitrogen (N) loss from agricultural systems. Recently, the rice rhizosphere was demonstrated to be a hotspot for Anammox, yet the dynamics of Anammox activity and the distribution of Anammox bacteria in rhizosphere soil at different phenological stages of rice growth are still unknown. In this study, the activity, diversity and abundance of Anammox bacteria in both rhizosphere and bulk soils were investigated over the entire rice growth season. From tillering to ripening stage, significantly higher Anammox bacterial abundance was detected in rhizosphere soils compared to bulk soils. The rhizosphere soils also had significantly higher Anammox rates at tillering and booting stages (0.71 and 0.32 nmol N g −1 dry soil h −1 , respectively) compared to bulk soils. The Anammox rate in rhizosphere soil was positively correlated to the concentrations of NO x − (total of nitrate and nitrite) and acetate. The abundance of Anammox bacteria was significantly correlated with the concentration of succinate in rhizosphere soils. A total of five Anammox genera of Brocadia , Kuenenia , Anammoxoglobus , Jettenia and Scalindua were detected, with Brocadia predominating in all examined samples. The distribution of Anammox bacteria in rhizosphere and bulk soils varied with phenological stages. Statistical analysis indicated that C/N ratio, formate, citrate and ammonium were key factors influencing the composition of Anammox bacteria. Variations in activity, abundance and distribution of Anammox bacteria in rhizosphere were observed over the phenological progression, demonstrating that the root exudates might be influential for the Anammox process. This study implies that future efforts in estimating the rate of Anammox should consider the temporal variation during plant life cycles.
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potential contribution of Anammox to nitrogen loss from paddy soils in southern china
Applied and Environmental Microbiology, 2015Co-Authors: Xiao-ru Yang, Guibing Zhu, Sanan Nie, Bosen Weng, Jack A Gilbert, Huaiying Yao, Yong-guan ZhuAbstract:The anaerobic oxidation of ammonium (Anammox) process has been observed in diverse terrestrial ecosystems, while the contribution of Anammox to N2 production in paddy soils is not well documented. In this study, the Anammox activity and the abundance and diversity of Anammox bacteria were investigated to assess the Anammox potential of 12 typical paddy soils collected in southern China. Anammox bacteria related to "Candidatus Brocadia" and "Candidatus Kuenenia" and two novel unidentified clusters were detected, with "Candidatus Brocadia" comprising 50% of the Anammox population. The prevalence of the Anammox was confirmed by the quantitative PCR results based on hydrazine synthase (hzsB) genes, which showed that the abundance ranged from 1.16 × 10(4) to 9.65 × 10(4) copies per gram of dry weight. The Anammox rates measured by the isotope-pairing technique ranged from 0.27 to 5.25 nmol N per gram of soil per hour in these paddy soils, which contributed 0.6 to 15% to soil N2 production. It is estimated that a total loss of 2.50 × 10(6) Mg N per year is linked to Anammox in the paddy fields in southern China, which implied that ca. 10% of the applied ammonia fertilizers is lost via the Anammox process. Anammox activity was significantly correlated with the abundance of hzsB genes, soil nitrate concentration, and C/N ratio. Additionally, ammonia concentration and pH were found to be significantly correlated with the Anammox bacterial structure.