Distribution Of Ammonia-oxidizing Bacteria Research Articles

Response of ammonia-oxidizing archaea to heavy metal contamination in freshwater sediment

It has been well-documented that the distribution of ammonia-oxidizing bacteria (AOB) and archaea (AOA) in soils can be affected by heavy metal contamination, whereas information about the impact of heavy metal on these ammonia-oxidizing microorganisms in freshwater sediment is still lacking. The present study explored the change of sediment ammonia-oxidizing microorganisms in a freshwater reservoir after being accidentally contaminated by industrial discharge containing high levels of metals. Bacterial amoA gene was found to be below the quantitative PCR detection and was not successfully amplified by conventional PCR. The number of archaeal amoA gene in reservoir sediments were 9.62 × 102–1.35 × 107 copies per gram dry sediment. AOA abundance continuously decreased, and AOA richness, diversity and community structure also considerably varied with time. Therefore, heavy metal pollution could have a profound impact on freshwater sediment AOA community. This work could expand our knowledge of the effect of heavy metal contamination on nitrification in natural ecosystems.

Abundance and community structure of ammonia-oxidizing bacteria in activated sludge from different geographic regions in China.

Detailed ecological information on ammonia-oxidizing bacteria (AOB) in activated sludge of wastewater treatment plants (WWTPs) is very important to improve the efficiency of wastewater treatment. In this study, activated sludge samples were collected from seven municipal WWTPs located in seven cities in China, and real-time quantitative polymerase chain reaction (qPCR), as well as construction of clone libraries combined with correlation-based data analysis was performed. Further, the effect of geographic distribution and some water quality parameters on the ecological distribution of AOB in activated sludge from WWTPs were investigated. The geographic distribution, the influent concentration of total nitrogen (TN) and ammonia nitrogen (NH4+-N) had significant effects on the abundance of AOB (P < 0.05). However, the community structure of AOB were not significantly affected by geographic distribution, but by water quality parameters including the concentrations of TN and NH4+-N. N. oligotropha lineage was the dominant AOB group in the wastewater treatment systems. The results obtained in this study provide useful information to understand some aspects of the ecological information and influencing factors of AOB in geographically distributed WWTPs.

Aggregate Size Distribution of Ammonia-Oxidizing Bacteria and Archaea at Different Landscape Positions

ABSTRACTTo quantify the spatial distribution of ammonia-oxidizing bacteria (AOB) and archaea (AOA) and to determine nitrification activity in soil aggregates along a landscape, soil samples were collected from three landscape positions (shoulder, backslope, and toeslope) at two pasture sites with contrasting climatic conditions. The abundance of AOB and AOA was estimated by quantifying their respective bacterial and archaeal amoA gene copies using real-time polymerase chain reaction. Soil organic C (SOC), total N (TN), and the potential nitrification rate (PNR) were measured in aggregate size ranges (4–1, 1–0.25, and 0.25–0.05 mm). At site 1, a decreasing trend in PNR was observed as the size of aggregates decreased. Both bacterial and archaeal amoA genes were higher in the macroaggregates (4–1 and 1–0.25 mm) than in the microaggregates (0.25–0.05 mm) along the landscape. At site 2, PNR was higher in the smallest size of aggregates. In the 0.25–0.05-mm fraction, the abundance of bacterial and archaeal amoA genes was equal to, or greater than, those found in larger aggregate sizes. The relative abundance of archaeal amoA gene and the PNR correlated with relative SOC and TN contents along the landscapes. The positive relationship between relative archaeal amoA gene abundance and PNR suggests that nitrification in the studied pastures is probably driven by ammonia-oxidizing Thaumarchaeota.

Abundance and distribution of ammonia-oxidizing microorganisms in the sediments of Beiyun River, China

Ammonia oxidation, driven by ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB), plays an important role in the global nitrogen cycle. However, the population and distribution of ammonia-oxidizing microorganisms in the sediments of urban rivers with intensive anthropogenic nitrogen inputs is still unclear. In this study, we compared the diversity and abundance of AOA and AOB in Beiyun River sediments from summer to winter. AOB dominated numerically over AOA and the abundance of both the amoA genes were much higher in winter than in summer, while AOA communities were more phylogenetically diverse than AOB in this study area. Phylogenetic analysis revealed that Nitrosospira sp. was the dominant AOB in summer, with Nitrosomonas sp. dominant in winter, while no specific genus was found for AOA in present study. The main pollutants and microbial communities in the sediments deriving from Yangwa Watergate were different from other sites. Clone libraries showed that a considerable percentage of amoA sequences matched closely with those from wastewater treatment plant (WWTP) systems. The seasonal change in nitrate content was significantly and positively related to the seasonal variation in amoA abundance (P < 0.05). Total nitrogen, total organic carbon, ammonium, and pH were the main environmental factors accounting for the difference in community composition of ammonia-oxidizing microorganisms in the sediments of Beiyun River. These findings suggest that effluent inputs, water gate operation, and seasonal changes might be key factors determining the abundance and distribution of AOB and AOA in the sediments of urban rivers.

Bacterial Domination Over Archaea in Ammonia Oxidation in a Monsoon-Driven Tropical Estuary

Autotrophic ammonia oxidizing microorganisms, which are responsible for the rate-limiting step of nitrification in most aquatic systems, have not been studied in tropical estuaries. Cochin estuary (CE) is one of the largest, productive, and monsoon-driven estuary in India opening into the southeast Arabian Sea. CE receives surplus quantities of ammonia through industrial and domestic discharges. The distribution of ammonia-oxidizing bacteria (AOB), ammonia-oxidizing archaea (AOA), and anaerobic ammonia-oxidizing bacteria (anammox) were studied using fluorescence in situ hybridization (FISH) and their relative contribution to the process as well as the governing factors were examined and reported for the first time from CE. The order of occurrence of these assemblages was β-proteobacteria (0.79 to 2 × 10(5) cells ml(-1)) > γ-proteobacteria (0.9 to 4.6 × 10(4) cells ml(-1)) > anammox (0.49 to 1.9 × 10(4) cells ml(-1)) > AOA (0.56 to 6.3 × 10(3) cells ml(-1)). Phylogenetic analysis of DGGE bands showed major affiliation of AOB to β-proteobacteria, while AOA was affiliated to Crenarchaeota. The abundance of AOB was mostly influenced by ammonia concentrations. The recovered ammonia oxidation rate of AOB was in the range of 45-65%, whereas for AOA, it was 15-45%, indicating that AOB were mostly responsible for the ammonia oxidation in CE during the study period. Overall, the present study provides an insight into the relevance and contribution of different groups of ammonia oxidizing bacteria in CE and emphasizes the need for further in depth studies across space and on season scale.

Spatial distribution of ammonia-oxidizing bacteria in the biofilm and suspended growth biomass of the full- and partial-bed biological aerated filters

The extent of comparable nitrogen removal in the full- and partial-bed biological aerated reactors needs further microbiological evidence, specifically the existence of ammonia-oxidizing bacteria (AOB). The nitrogen removal process in such systems is typically initiated by chemoliautotrophic ammonia-oxidizing bacteria converting ammonia to nitrite and traces of oxidized nitrogen gases. The formation of a dense biofilm as a result of higher turbulence would account for the higher number of AOB cells enumerated in the biofilm samples from the partial-bed reactor (4·3 × 105 ± 1·9 × 105 No. of AOB cells/mL sample) as compared with those from the full-bed reactor (1·5 × 105 ± 8·0 × 104 No. of AOB cells/mL sample).

Influence of Salinity on Distribution of Ammonia-Oxidizing Bacteria in Laohe Estuarine Wetland, China

Soil salinization in Laohe estuarine wetland is becoming more serious, thus the characteristics of AOB in different salt salinity have drawn more attention. Our study investigated the spatial and temporal distribution of ammonia-oxidizing bacteria (AOB) in different salinity soils in Laohe estuarine wetland. Results show that the largest amount of AOB appeared when salinity was 10g/kg, and decrease when salinity was higher (15g/kg, 20g/kg) or lower (2g/kg, 5g/kg). The distribution of AOB shows that the AOB amount is larger in surface layer (0-20cm) than middle layer (20-40cm) or the bottom layer (40-60cm); the AOB is more abundant in summer than autumn. Results indicate that salinity is a key factor on the AOB abundance, but not an influencer on the vertical and temporal distribution of AOB in estuarine wetland. Temperature and organic content are the related factors of the vertical distribution of AOB abundance, and the growth of reed is also an important influence factor on the variation of AOB during different seasons.

Study on the factors affecting simultaneous removal of ammonia and manganese by pilot-scale biological aerated filter (BAF) for drinking water pre-treatment

It was demonstrated that simultaneous removal of ammonia and manganese could be accomplished by biological aerated filter (BAF) with low-cost lava as media. Long-term operation performance and impact factors were systematically studied. DGGE analysis demonstrated that ammonia oxidizing bacteria (AOB), manganese oxidizing bacteria (MOB) and simultaneous ammonia and manganese oxidizing bacteria (SAMOB) co-existed in the bio-film. Ammonia and manganese concentration profiles along the height of BAF column, including that in the influent and effluent, were investigated with varying hydraulic loadings, aeration intensities and feed ammonia concentrations. It was inferred that AOB and MOB may have different spatial distribution in vertical direction, and AOB and MOB may compete for oxygen capture or be present on different layers of the bio-films. Further work should focus on the distribution of AOB, MOB and SAMOB in the reactor and optimize it for more efficient mass transfer and better system performance.

Abundance of ammonia-oxidizing bacteria and archaea in industrial and domestic wastewater treatment systems

Nitrification plays a significant role in the global nitrogen cycle. Ammonia oxidation, the first step of nitrification, is performed in wastewater treatment by both ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA). Most previous studies focused on their distribution in natural environments. In this study we qualified and quantified AOB, AOA, total bacteria, and total archaea in six different wastewater treatment systems (WTSs) using clone library and real-time PCR techniques. The results revealed that wastewater quality was an essential factor for the distribution of AOB and AOA in aerobic reactors. Although both AOB and AOA were present in all samples and contributed to nitrification simultaneously, AOB were the dominant nitrifiers in the three industrial WTSs, whereas AOA were dominant in the three domestic WTSs. This indicates AOA may be more sensitive to some toxic compounds than AOB. In addition, the dominant groups of AOB in the industrial WTSs were Nitrosomonas and Nitrosospira; the composition of AOA in the domestic WTSs was very similar, possibly due to the same source of raw sewage.

Abundance and community structure of ammonia-oxidizing bacteria and archaea in a temperate forest ecosystem under ten-years elevated CO 2

Ammonia-oxidizing bacteria (AOB) and archaea (AOA) are considered as the key drivers of global nitrogen (N) biogeochemical cycling. Responses of the associated microorganisms to global changes remain unclear. This study was to determine if there was a shift in soil AOB and AOA abundances and community structures under free-air carbon dioxide (CO 2) enrichment (FACE) and N fertilization in Duke Forest of North Carolina, by using DNA-based molecular techniques, i.e., quantitative PCR, restriction fragment length polymorphism (RFLP) and clone library. The N fertilization alone increased the abundance of bacterial amoA gene, but this effect was not observed under elevated CO 2 condition. There was no significant effect of the N fertilization on the thaumarchaeal amoA gene abundance in the ambient CO 2 treatments, while such effect increased significantly under elevated CO 2. A total of 690 positive clones for AOA and 607 for AOB were selected for RFLP analysis. Analysis of molecular variance (AMOVA) indicated that effects of CO 2 enrichment and N fertilization on the community structure of AOA and AOB were not significant. Canonical correspondence analysis also showed that soil pH rather than elevated CO 2 or N fertilization shaped the distribution of AOB and AOA genotypes. A negative linear relationship between the δ 13C and archaeal amoA gene abundance indicated a positive effect of elevated CO 2 on the growth ammonia oxidizing archaea. On the other hand, the community structures of AOB and AOA are determined by the soil niche properties rather than elevated CO 2 and N fertilization.

Dynamic and distribution of ammonia-oxidizing bacteria communities during sludge granulation in an anaerobic–aerobic sequencing batch reactor

The structure dynamic of ammonia-oxidizing bacteria (AOB) community and the distribution of AOB and nitrite-oxidizing bacteria (NOB) in granular sludge from an anaerobic–aerobic sequencing batch reactor (SBR) were investigated. A combination of process studies, molecular biotechniques and microscale techniques were employed to identify and characterize these organisms. The AOB community structure in granules was substantially different from that of the initial pattern of the inoculants sludge. Along with granules formation, the AOB diversity declined due to the selection pressure imposed by process conditions. Denaturing gradient gel electrophoresis (DGGE) and sequencing results demonstrated that most of Nitrosomonas in the inoculating sludge were remained because of their ability to rapidly adapt to the settling–washing out action. Furthermore, DGGE analysis revealed that larger granules benefit more AOB species surviving in the reactor. In the SBR were various size granules coexisted, granule diameter affected the distribution range of AOB and NOB. Small and medium granules (d < 0.6 mm) cannot restrict oxygen mass transfer in all spaces of the sludge. Larger granules (d > 0.9 mm) can result in smaller aerobic volume fraction and inhibition of NOB growth. All these observations provide support to future studies on the mechanisms responsible for the AOB in granules systems.

Spatial distribution of ammonia-oxidizing bacteria in the biofilm and suspended growth biomass of the full- and partial-bed biological aerated filtersA paper submitted to the Journal of Environmental Engineering and Science.

The extent of comparable nitrogen removal in the full- and partial-bed biological aerated reactors needs further microbiological evidence, specifically the existence of ammonia-oxidizing bacteria (AOB). The nitrogen removal process in such systems is typically initiated by chemoliautotrophic ammonia-oxidizing bacteria converting ammonia to nitrite and traces of oxidized nitrogen gases. The formation of a dense biofilm as a result of higher turbulence would account for the higher number of AOB cells enumerated in the biofilm samples from the partial-bed reactor (4.3 × 105 ± 1.9 × 105No. of AOB cells/mL sample) as compared with those from the full-bed reactor (1.5 × 105 ± 8.0 × 104No. of AOB cells/mL sample).

Distribution and Rate of Microbial Processes in an Ammonia-Loaded Air Filter Biofilm

The in situ activity and distribution of heterotrophic and nitrifying bacteria and their potential interactions were investigated in a full-scale, two-section, trickling filter designed for biological degradation of volatile organics and NH(3) in ventilation air from pig farms. The filter biofilm was investigated by microsensor analysis, fluorescence in situ hybridization, quantitative PCR, and batch incubation activity measurements. In situ aerobic activity showed a significant decrease through the filter, while the distribution of ammonia-oxidizing bacteria (AOB) was highly skewed toward the filter outlet. Nitrite oxidation was not detected during most of the experimental period, and the AOB activity therefore resulted in NO(2)(-), accumulation, with concentrations often exceeding 100 mM at the filter inlet. The restriction of AOB to the outlet section of the filter was explained by both competition with heterotrophic bacteria for O(2) and inhibition by the protonated form of NO(2)(-), HNO(2). Product inhibition of AOB growth could explain why this type of filter tends to emit air with a rather constant NH(3) concentration irrespective of variations in inlet concentration and airflow.

Seasonal effect on N 2O formation in nitrification in constructed wetlands

Constructed wetlands are considered to be important sources of nitrous oxide (N 2O). In order to investigate the contribution of nitrification in N 2O formation, some environmental factors, plant species and ammonia-oxidizing bacteria (AOB) in active layers have been compared. Vegetation cells indicated remarkable effect of seasons and different plant species on N 2O emission and AOB amount. Nitrous oxide data showed large temporal and spatial fluctuations ranging 0–52.8 mg N 2O m −2 d −1. Higher AOB amount and N 2O flux rate were observed in the Zizania latifolia cell, reflecting high potential of global warming. Roles of plants as ecosystem engineers are summarized with rhizosphere oxygen release and organic matter transportation to affect nitrogen transformation. The Phragmites australis cell contributed to keeping high T-N removal performance and lower N 2O emission. The distribution of AOB also supported this result. Statistical analysis showed several environmental parameters affecting the strength of observed greenhouse gases emission, such as water temperature, water level, TOC, plant species and plant cover.

Comparative analysis of ammonia monooxygenase (amoA) genes in the water column and sediment–water interface of two lakes and the Baltic Sea

The functional gene amoA was used to compare the diversity of ammonia-oxidizing bacteria (AOB) in the water column and sediment-water interface of the two freshwater lakes Plusssee and Schöhsee and the Baltic Sea. Nested amplifications were used to increase the sensitivity of amoA detection, and to amplify a 789-bp fragment from which clone libraries were prepared. The larger part of the sequences was only distantly related to any of the cultured AOB and is considered to represent new clusters of AOB within the Nitrosomonas/Nitrosospira group. Almost all sequences from the water column of the Baltic Sea and from 1-m depth of Schöhsee were related to different Nitrosospira clusters 0 and 2, respectively. The majority of sequences from Plusssee and Schöhsee were associated with sequences from Chesapeake Bay, from a previous study of Plusssee and from rice roots in Nitrosospira-like cluster A, which lacks sequences from Baltic Sea. Two groups of sequences from Baltic Sea sediment were related to clonal sequences from other brackish/marine habitats in the purely environmental Nitrosospira-like cluster B and the Nitrosomonas-like cluster. This confirms previous results from 16S rRNA gene libraries that indicated the existence of hitherto uncultivated AOB in lake and Baltic Sea samples, and showed a differential distribution of AOB along the water column and sediment of these environments.

Population dynamics and in situ kinetics of nitrifying bacteria in autotrophic nitrifying biofilms as determined by real‐time quantitative PCR

Population dynamics of ammonia-oxidizing bacteria (AOB) and uncultured Nitrospira-like nitrite-oxidizing bacteria (NOB) dominated in autotrophic nitrifying biofilms were determined by using real-time quantitative polymerase chain reaction (RTQ-PCR) and fluorescence in situ hybridization (FISH). Although two quantitative techniques gave the comparable results, the RTQ-PCR assay was easier and faster than the FISH technique for quantification of both nitrifying bacteria in dense microcolony-forming nitrifying biofilms. Using this RTQ-PCR assay, we could successfully determine the maximum specific growth rate (mu = 0.021/h) of uncultured Nitrospira-like NOB in the suspended enrichment culture. The population dynamics of nitrifying bacteria in the biofilm revealed that once they formed the biofilm, the both nitrifying bacteria grew slower than in planktonic cultures. We also calculated the spatial distributions of average specific growth rates of both nitrifying bacteria in the biofilm based on the concentration profiles of NH4+, NO2-, and O2, which were determined by microelectrodes, and the double-Monod model. This simple model estimation could explain the stratified spatial distribution of AOB and Nitrospira-like NOB in the biofilm. The combination of culture-independent molecular techniques and microelectrode measurements is a very powerful approach to analyze the in situ kinetics and ecophysiology of nitrifying bacteria including uncultured Nitrospira-like NOB in complex biofilm communities.

Distribution of ammonia-oxidizing bacteria in sewage activated sludge: analysis based on 16S rDNA sequence

This study carried out analysis of ammonia-oxidizing bacteria (AOB) communities in 12 sewage activated sludge systems standing in eight sewage treatment plants located in Tokyo. The systems were different in the treatment process configuration: anaerobic/anoxic/aerobic (A20), anaerobic/aerobic (AO), and conventional activated sludge (AS) processes. AOB communities were analyzed by sequences of 16S rDNA amplicons, which were separated by denaturing gradient gel eletrophoresis (DGGE) after specific polymerase chain reaction (PCR) amplification. The results demonstrated that low ammonium concentrations in the influents of the 12 sewage activated sludge systems resulted in the dominance of Nitrosomonas oligotropha-like sequences. Further, Nitrosomonas europaea- and Nitrosomonas cryotolerans-like sequences were recovered from only one A20 system of which the influent contained higher ammonium and chloride concentrations than those of other systems. Nitrosomonas communis-like sequences were found in every A20 and AO system, but mostly not found in every AS system. In summary, influent characteristics and treatment process configuration affected the AOB communities in the 12 sewage activated sludge systems.

The numbers and distribution of ammonia-oxidizing bacteria in some Northern Territory and South Australian soils

Ammonia-oxidizing bacteria were detected in 75 soil samples from the Northern Territory and South Australia. Silica gel plates gave soil counts comparable with those obtained in liquid media. The counts varied from 20 to 8000 cells per gram of soil. Nitrosogloea merismoides was detected in 53 of the soils, Nitrosornonas europaea in 39 soils, and Nitrosococcus nitrosus in 14 soils. There was little difference between the numbers and types of nitrifying bacteria present in the desert soils compared with those from the more temperate areas, nor did the average annual rainfall have any appreciable effect.