Jettenia Asiatica Research Articles

Optimization of two CSTRs using granular sludges dominated by Ca. Jettenia asiatica and Ca. Brocadia sinica

Two CSTRs using granules dominated by Ca. Jetteni asiatica (R1) and Ca. Brocadia sinica (R2) were operated depending on influent T-N concentrations and HRT. R1 achieved the highest NRR of 1.64 kgN/m3/day at HRT 8 h and T-N 600 mg/L, while R2 obtained the highest NRR of 2.05 kgN/m3/day at HRT 4 h and T-N 400 mg/L. The both reactors achieved high performance in high T-N concentration with the increasing of HRT in relatively short time. The sufficient T-N concentration and favorable short HRT were giving significant effects in promoting biomass increment and maintaining high removal in R1 and R2. In R1, granules larger than 2 mm accounted for over 60 %, while in R2 granules in the range of 1-2 mm comprised approximately 60 %. Granules in R1 were relatively harder and denser, and the surface of granules in R1 appeared rough, whereas the surface of granules in R2 seemed smoother. The abundance of anammox bacteria were much improved in both R1 and R2, operating under optimal operational conditions, showed significant improvement. The distribution of Ca. Brocadia sinica increased from 2.6 % to 42.0 % for R1 and from 9.1 %, to 90.5 % for R2, while there was little change in Ca. Jettenia asiatica. In this study, while the optimal HRT and nitrogen concentration as influent varied depending on the dominant anammox bacteria and granule characteristics in the inoculum, Ca. Brocadia sinica appears to play a significant role in nitrogen removal.

Utilization of three-layered polyvinyl alcohol gel cubes for treating low-strength ammonium wastewater in a single-stage autotrophic nitrogen removal process

This study examined the feasibility of using a three-layered polyvinyl alcohol (PVA) gel cube for low-strength ammonium wastewater (<50 mg-NH4+-N/L) treatment in a single reactor. The outer layer of this three-layered PVA gel cube was composed of immobilized nitrifying bacteria, while the inner layers were composed of anaerobic ammonium oxidation (anammox) bacteria. A single-stage autotrophic nitrogen removal (SANR) reactor containing these three-layered PVA gel cubes was operated at 35 °C for 197 days, with intermittent aeration. Although the activity of nitrite-oxidizing bacteria (NOB) was incompletely inhibited under a narrow range of dissolved oxygen (DO) concentrations (0.1–1.1 mg-O2/L), a nitrogen removal efficiency (NRE) of 71.9% was achieved at 35 °C. At this temperature, the high NRE was achieved due to the coexistence of anammox and denitrifying bacteria. After decreasing the temperature to 20 °C, the NRE was maintained at a similar level (69.8%) for 53 days. The change in the structure of the bacterial community was insignificant with decreasing temperature. The 16S rRNA high-throughput sequencing analysis revealed that Planctomycetes (46.8–53.4%) was the most abundant phylum, wherein anammox bacteria accounted for 45.4–51.9% of the relative biodiversity abundance. Candidatus Jettenia asiatica disappeared for the operation of 187 days, while Candidatus Brocadia sinica was abundant. After 220 days, the relative abundances of ammonium-oxidizing bacteria (AOB) and NOB doubled and tripled, respectively. The abundant AOB were Nitrosomonas aestuarii and Nitrosomonas ureae, while the dominant NOB was Nitrospira moscoviensis. Nitrate produced by undesirable NOB activity was converted to nitrite by Denitratisoma oestradiolicum, which led to the abundance of anammox bacteria.

Effect of inorganic carbon limitation on the nitrogen removal performance of the single-stage reactor containing anammox and nitritation gel carriers

Herein, the effect of inorganic carbon (IC) limitation on the nitrogen removal performance of the single-stage reactor containing nitritation and anammox gel carriers was investigated. As a result of a continuous feeding test, the effluent ammonium concentration increased as the IC concentration decreased, indicating the deterioration of nitritation activity, not anammox. Furthermore, the sensitivity of IC to anammox and nitritation activity was investigated in anammox and nitritation reactors, respectively. Consequently, the relationship between the effluent IC concentration and nitritation rate was well described using the Michaelis-Menten equation. The apparent Km value of nitritation was calculated as 4.4mg-C L-1. In anammox reactor, it was calculated as 1.7mg-C L-1. These results revealed that the affinity of nitritation gel carriers to IC was lower than that of anammox, supporting that nitritation activity was easily deactivated by decrease in the IC concentration rather than anammox. Microbial community analysis revealed that Nitrosomonas europaea and Candidatus Jettenia asiatica were the dominant species of ammonium-oxidizing and anammox bacteria.

An Analysis of Operation Conditions and Microbial Characteristics in Swine Wastewater Treatment Plants with Spontaneously Enriched Anammox Bacteria

The spontaneous enrichment of anammox bacteria has been reported in swine wastewater treatment facilities. However, their causative conditions and microbial characteristics, which this study aims to explain, are poorly understood. We discovered eight treatment facilities where the collected red biofilms exhibited high anammox activity levels at 57–843 µmol-N2/g-ignition loss (IL)/h and anammox DNA concentrations of 4.3 × 108–1.6 × 1012 copies/g-IL. The facilities used various wastewater treatment methods—six of them employed a multi-stage continuous reactor, whereas aeration tanks were continuously aerated at another combination of six facilities. Levels of dissolved oxygen (DO) in these tanks were fairly low at ≤1 mg/L. Pyrosequencing of the biofilms indicated the presence of 3–62.5% Planctomycetes, and the dominant anammox in each biofilm comprised three operational taxonomic units (OTUs) similar to Candidatus Jettenia asiatica, Ca. Brocadia fulgida, and Ca. B. caroliniensis. This suggested that some particular species of anammox bacteria naturally thrive when operating a swine wastewater treatment facility at low DO levels. The frequent enrichment of anammox biofilms at the sampled sites indicated that these treatment facilities were good seed sources of anammox; therefore, anammox treatment would be a viable method for the removal of nitrogen from swine wastewater.

Adaptation of anammox granules in swine wastewater treatment to low temperatures at a full-scale simultaneous partial nitrification, anammox, and denitrification plant

In the anammox process, maintaining a high anammox activity at low water temperatures for stable nitrogen removal is a challenge. In this study, to verify the adaptability of anammox to low water temperatures, we investigated effects of annual temperature fluctuations on nitrogen removal in a full-scale swine wastewater treatment plant, where anammox bacteria accumulated. Annual quarters were defined as L-1 (November–January), L-2 (February–April), H-1 (April–July), and H-2 (July–October). The total nitrogen removal rate was stable at 0.08–0.11 kg-N/m3/d, even during temperature fluctuations. Removal efficiencies of biochemical oxygen demand and total nitrogen were consistently high at 95–99% and 69–81%, respectively. The anammox activity and abundance of anammox bacteria were highest in granule L-1 and lowest in granule H-2. The optimal temperature for anammox activity shifted from 35 °C in granules H-1 and H-2 to 30 °C in granules L-1 and L-2, while the latter maintained a moderate activity compared to the former at low temperature. Candidatus Jettenia asiatica was predominant, especially in granule L-2, accounting for up to 54% of the microbial community composition at the genus level. The high specific anammox activity in granule L-2 was considered to be due to the abundance of anammox bacteria and the adaptation of Ca. Jettenia asiatica to low temperature. The anammox granules adapted well to low temperatures and demonstrated high efficiency in the simultaneous partial nitrification anammox and denitrification process without heating. Thus, constructing an energy-saving and cost-effective nitrogen removal system can be considered.

Low-ammonia wastewater treatment by integration of partial nitritation and anaerobic ammonium oxidation (anammox) at 20 ℃

This study investigated a combined partial nitritation and anammox process for treating low-strength ammonia synthetic wastewater (~50 mg-NH4+-N/L) at 20 °C. The nitrifying bioreactor consisted of immobilized nitrifying bacteria in poly(vinyl alcohol) gel beads, which was operated under limited dissolved oxygen (DO) concentrations of 0.3–0.5 mg-O2/L to suppress nitrite-oxidizing bacteria (NOB) activity. The temperature in the nitrifying bioreactor decreased from 35 °C to 20 °C, and the hydraulic retention time (HRT) was shortened from 6 h to 3 h. The limited DO concentration enabled partial oxidation of ammonia to nitrite (55.8%), but an undesired nitrite oxidation rate of 31.5% was observed at 20 °C. The changes in bacterial community structure in response to the different operating conditions were observed by high-throughput 16S rRNA gene sequencing analysis. The lowered temperature resulted in a significant shift in the bacterial community structure, while the effect of HRT was negligible. Nitrosomonas ureae and Nitrospira moscoviensis played critical roles in nitrification at low DO concentrations. Interestingly, a high nitrogen-removal efficiency of 71.4% was achieved in the integrated nitrifying bioreactor and anammox at 20 °C despite incomplete NOB suppression in the nitrifying bioreactor. Denitratisoma oestradiolicum and Petrimonas sp., which are capable of nitrate reduction, were dominant in the anammox reactor, which might allow the provision of additional nitrite for the anammox reaction. The number of Candidatus Jettenia asiatica decreased in response to the lowered temperature, while the population of Candidatus Brocadia sinica increased.

Methanol tolerance and acclimation in the anammox process using a gel carrier

• Tolerant level of methanol was determined using MBBR using gel carriers. • No significant effect up to 30 mg L −1 , but irreversible inhibition at 40 mg L −1 . • By gradually increasing from 5 mg L −1 , no inhibitory effect even at 100 mg L −1 . • Heterotrophic denitrification contributed methanol consumption. • Methylotrophs such as Hyphomicrobiaceae was confirmed in the gel carriers. The methanol tolerance level of the anammox process was investigated in continuous feeding tests. In the conducted pulse methanol addition tests of gel carrier-immobilized anammox bacteria, the nitrogen removal performance was not significantly affected at influent methanol concentrations of up to 30 mg L −1 ; however, irreversible inhibition occurred at 40 mg L −1 . In the absence of methanol acclimation, the anammox process showed low methanol tolerance levels. Moreover, the stepwise addition of 5 mg L −1 of methanol resulted in no anammox inhibition even when the methanol concentration became 100 mg L −1 . The effluent total organic carbon concentration did not increase with the increase in the influent methanol concentration; this indicates that methanol was consumed along with the nitrate or nitrite by heterotrophic denitrification. These results show that the increase in the methanol tolerance level was due to the increase in the methanol consumption ability during the anammox process because of the increased denitrifying bacteria and not because the anammox bacteria exhibited resistance to methanol. The microbial community analysis revealed the dominant species in the gel carriers ( Candidatus Jettenia asiatica), existence of methylotrophic bacteria, and growth in the methanol-consuming bacterial population.

Anaerobic ammonium oxidation is a major N-sink in aquifer systems around the world.

Global-scale N-oxide contamination of groundwater within aquifers occurs due to the widespread use of N-bearing fertilizers and chemicals, threatening both human and environmental health. However, the conversion of these pollutants in active nitrogen (N) cycling processes in the subsurface biosphere still remains unclear. This study investigates the global occurrence of anaerobic ammonium oxidation (anammox) in aquifers, where anammox was found to be turned on and off between saturated and unsaturated soil horizons, and contributed 36.8-79.5% to N loss in saturated soil horizons, the remainder being due to denitrification which has traditionally been considered the main pathway for removal of N-pollutants from aquifers. Although anammox activity was undetectable in the unsaturated soil horizons, it could potentially be activated by contact with ascending groundwater. High-throughput pyrosequencing analysis identified Candidatus Brocadia anammoxidans as being the most abundant anammox bacterium in the saturated soils investigated. However, the anammox bacterial abundance was determined by the relative richness of Candidatus Jettenia asiatica. Isotopic pairing experiments revealed that coupling anammox with ammonium oxidation and respiratory ammonification enabled the formation of a revised N cycle in aquifer systems, in which respiratory ammonification acted as an important coordinator. Anammox can therefore contribute substantially to aquifer N cycling and its role in remediation of aquifers contaminated with N-oxides may be of global importance.

NanoSIMS reveals unusual enrichment of acetate and propionate by an anammox consortium dominated by Jettenia asiatica

Anaerobic ammonium-oxidizing (anammox) bacteria convert ammonium and nitrite into N2 in a chemolithoautotrophic way, meaning that they utilize CO2/HCO3 solely as their carbon sources. Such autotrophic behavior limits their competitiveness with heterotrophic microorganisms in both natural environments and engineered systems. Recently, environmental metagenomic results have indicated the capability of anammox bacteria to metabolize short-chain fatty acids, further confirmed by limited experimental evidence based on highly enriched cultures. However, clear evidence is difficult to get because of the limits of traditional methodologies which rely on the availability of a pure anammox culture. In this study, we identified and quantified the uptake of acetate and propionate, on a single-cell level, by an anammox consortium that was dominated by Candidatus Jettenia asiatica (relative abundance of 96%). The consortium, growing in granular form with an average relative abundance of anammox bacteria of 96.0%, was firstly incubated in a13C-labelled acetate or propionate medium; then microtome sections were scanned by a nanometer-scale secondary ion mass spectrometer (NanoSIMS). The NanoSIMS scannings revealed that the consortium enriched acetate and propionate at a >10 times higher efficiency than bicarbonate incorporation. Our results also suggest that acetate or propionate was likely not assimilated by J. asiatica directly, but firstly oxidized to CO2, which then served as carbon sources for the follow-up autotrophy in J. asiatica cells. Furthermore, more [15N]ammonium was enriched by the propionate-fed consortium than the acetate-fed consortium despite that exactly the same amount of 13C atoms were supplied. Our study strongly indicates an alternative lifestyle, namely organotrophy, in addition to chemolithoautotrophy of anammox bacteria, making it more versatile than often expected. It suggests that the niche of anammox bacteria in both natural and engineered ecosystems can be much broader than usual assumed. Recognising this is important for their role in wastewater treatment and the global nitrogen turn-over rates.

Fast start-up of the cold-anammox process with different inoculums at low temperature (13 °C) in innovative reactor

Three innovative reactors (CAMBR) through optimally combining with the Anaerobic Baffled reactor and Membrane bioreactor were applied to start up the cold-anammox process at low temperature (13 °C) through inoculating flocculent nitrification sludge (R1), anaerobic granular sludge (R2) and flocculent denitrification sludge (R3), respectively. Results showed that anammox process was started successfully with over 90% total nitrogen removal rate in R1, R2 and R3 after 75d, 45d, and 90d, respectively. Microbial community revealed that Ca. Brocadia and Ca. Jettenia were the dominant anammox bacteria in R1, R2 and R3, accounting for an abundance of 0.08%, 12.18%; 3.17%, 0 and 0.08%, 0.38%, respectively. Three anammox species, Ca. Brocadia caroliniensis, Ca. Brocadia sinica and Ca. Jettenia asiatica were annotated based on the phylogenetic tree, suggesting the anammox species with larger maximum growth rate contributed to the rapid start-up of the cold-anammox process. This study reinforces the potential application of mainstream anammox.

Abundance and diversity of anammox bacteria in a mainstream municipal wastewater treatment plant.

Among the factors that obstruct the application of anammox-based technology for nitrogen removal from mainstream municipal wastewater is the water's high organic loads. We hypothesized that some anammox species can adapt and grow in mainstream wastewater in which a minimal temperature of 13-15°C is maintained. Using the AMX368F and AMX820R PCR-primers, anammox bacteria were detected in influent wastewater (COD/N ratio > 13) and in the anaerobic, anoxic, and aerobic chambers of a full-scale municipal wastewater treatment plant, reaching 107 copies/g VSS of the16S rRNA gene. Furthermore, anammox activity was demonstrated by 15N-isotopic tracing. The DNA sequences of clones randomly selected from a clone library were mainly clustered with Candidatus Brocadia flugida in addition to Ca. Brocadia sinica, Ca. Jettenia asiatica, and Ca. Anammoxoglobus propionicus. However, Ca. Brocadia was the only genus detected by high-throughput next-generation sequencing and denaturing gradient gel electrophoresis. The nitrite producers, ammonia-oxidizing archaea and bacteria, were both detected in the influent wastewater and the other chambers, while the nitrite consumers, Nitrospira nitrite oxidizers and the nirS-type denitrifiers, dominated all chambers. The results indicate the occurrence and potential activity of anammox bacteria in mainstream wastewater under certain conditions (proper temperature). The dominance of Brocadia flugida and Anammoxoglobus propionicus suggests a role for volatile fatty acids in selecting the anammox community in wastewater.

Mainstream upflow nitritation-anammox system with hybrid anaerobic pretreatment: Long-term performance and microbial community dynamics

Mainstream nitritation-anammox is of strong interest to energy- and resource-efficient domestic wastewater treatment. However, there lack in-depth studies of pretreatment, tests of actual wastewater, and examination of long-term performance. Herein, an upflow nitritation-anammox granular reactor has been investigated to treat primary effluent with a hybrid anaerobic reactor (HAR) as pretreatment for more than 300 days. This system achieved 92% of COD removal, 75% of which was accomplished by the HAR, and had an average final effluent COD concentration of 22 mg L−1. More than 90% of ammonium was removed in the nitritation-anammox reactor, achieving a nitrogen removal rate of 81.0 g N m−3 d−1 in the last stage. The accumulation of sulfate-reducing bacteria in the HAR evidenced the effect of sulfate on COD removal and subsequent nitrogen removal. Anammox bacteria (predominantly Ca. Jettenia asiatica) accounted for up to 40.2% of total granular communities, but their abundance decreased over time in the suspended communities. The dynamics of major metabolisms and functional genes involved in nitrogen conversion were predicted by PICRUSt based on the taxonomic data, providing more insights into the functions of the microbial communities. These results have demonstrated the effectiveness and importance of anaerobic pretreatment to successful mainstream nitritation-anammox.

Preservation and reactivation of Candidatus Jettenia asiatica and Anammoxoglobus propionicus using different preservative agents

Anaerobic ammonium oxidation (anammox) bacteria have peculiar characteristics that make them difficult to cultivate. The conservation of these microorganisms in culture collections or laboratories requires successful preservation and reactivation techniques. Furthermore, studies have shown that successful reactivation may be preservative dependent. Considering this, the present study aimed to evaluate the preservation and reactivation of anammox consortia enriched from swine manure treatment lagoons, by using different preservative agents at different temperatures: KNO3 (at 4 °C), glycerol (−20 °C, −80 °C), and skimmed cow milk (−20 °C, −80 °C, −200 °C). After 4 months, the biomass was thawed (except for KNO3), and the reestablishment of anammox activity was evaluated by stoichiometric coefficients. Microbial community transformation during the reactivation process was also studied by 16S rDNA sequence analysis. The results showed that the anammox biomass preserved with glycerol or skimmed cow milk at −80 °C recovered activity, while the biomass preserved with other methodologies did not reestablish activity during the studied time (90 days). The bacterial community from the biomass with anammox activity was characterized and showed the presence of Candidatus Brocadia anammoxidans, Candidatus Jettenia asiatica, and Candidatus Anammoxoglobus propionicus. Preservation with skimmed cow milk at −80 °C favored the selection of Candidatus Anammoxoglobus propionicus, while preservation with glycerol at −80 °C was successful for Candidatus Jettenia asiatica. The present study was effective on anammox sludge preservation and reactivation using low-cost processes for anammox cultures preservation, which is important for biomass transport and deammonification reactor start up.

Resuscitation of starved suspended- and attached-growth anaerobic ammonium oxidizing bacteria with and without acetate.

Anammox application for nutrient removal from wastewater is increasing, though questions remain about anammox resilience to fluctuating conditions. Resuscitation of anammox suspended- and attached-growth cultures after 3 months of starvation was studied with and without acetate dosing. Without acetate, the attached-growth culture recovered more quickly than the suspended-growth culture. Suspended-growth cultures recovered more quickly (within 60 days) with weekly and daily acetate dosing than without, but anammox activity and copy numbers decreased with continued acetate addition. All attached-growth cultures recovered within 60 days, but after that activity with acetate dosing was consistently at least 20% lower than that without acetate addition. Ca. Jettenia caeni, Ca. Anammoxoglobus sp., Ca. Brocadia fulgida, Ca. Brocadia anammoxidans, Ca. Brocadia fulgida and Ca. Jettenia asiatica were identified. Acetate addition can significantly accelerate short-term resuscitation of enriched anammox suspended-growth cultures after starvation but may reduce anammox activity over the longer term in suspended- and attached-growth cultures.

Contribution of Anammox to Nitrogen Removal in Two Temperate Forest Soils.

Anaerobic ammonium oxidation with nitrite reduction to dinitrogen (termed anammox) has been reported to be an important process for removing fixed nitrogen (N) in marine ecosystems and in some agricultural and wetland soils. However, its importance in upland forest soils has never been quantified. In this study, we evaluated the occurrence of anammox activity in two temperate forest soils collected from northeastern China. With (15)N-labeled NO3 (-) incubation, we found that the combined potential of the N2 production rates of anammox and codenitrification ranged from 0.01 ± 0.01 to 1.2 ± 0.18 nmol N per gram of soil per hour, contributing 0.5% to 14.4% of the total N2 production along the soil profile. Denitrification was the main pathway of N2 production and accounted for 85.6% to 99.5% of the total N2 production. Further labeling experiments with (15)NH4 (+) and (15)NO2 (-) indicated that codenitrification was present in the mixed forest soil. Codenitrification and anammox accounted for 2% to 12% and 1% to 7% of the total N2 production, respectively. Two anammox species, "Candidatus Brocadia fulgida" and "Candidatus Jettenia asiatica," were detected in this study but in very low abundance (as indicated by the hzsB gene). Our results demonstrated that the anammox process occurs in forest soils, but the contribution to N2 loss might be low in these ecosystems. More research is necessary to determine the activities of different N2 releasing pathways in different forest soils. In this study, we examined the anammox activity in temperate upland forest soils using the (15)N isotope technique. We found that the anammox process contributed little to the N2 production rate in the studied forest soil. Two anammox organisms, "Candidatus Brocadia fulgida" and "Candidatus Jettenia asiatica," were detected. In addition, we found that codenitrification was another N2 production pathway in forest soils. Our results could contribute to the understanding of soil gaseous N losses and microbial controls in forest soils.

High-rate nitrogen removal and microbial community of an up-flow anammox reactor with ceramics as biomass carrier

Nitrogen removal performance and responsible microbial community of anammox process at low temperatures, and long term effect of dissolved oxygen (DO) on the performance of anammox process were investigated in a biofilm reactor, which was operated at 33±1°C (159d) and 20±2°C (162d) with an influent DO concentration of 0.7–1.5mgL−1. Nitrogen removal recovered to 70% after 2wk with the temperature drastically decreasing from 33±1°C to 20±2°C. At 20±2°C, the average effluent (NH4+–N+NO2−–N) concentration was 0.08±0.08mgL−1 at a hydraulic retention time of 1.5h. A total nitrogen removal efficiency of the reactor of 1.0gNL−1d−1 was obtained for up to one month while the nitrogen loading rate was 1.16gNL−1d−1. Results of T-RFLP and 16S rRNA phylogenic analysis revealed that Candidatus Jettenia asiatica, as confirmed to adapt to low temperature, was considered to be responsible for the stable and high nitrogen removal performance.

C2/C3 fatty acid stress on anammox consortia dominated by Candidatus Jettenia asiatica

Anaerobic ammonium oxidation (anammox) is a promising technology for autotrophic removal of ammonium and nitrite. In order to expand its industrial application niche, effects of organic matter need more specific investigation. In this study, the effects of C2/C3 fatty acids stress on anaerobic ammonium oxidation (anammox) process were evaluated in batch experiments. BLAST search analysis of 16S rRNA sequences showed that the homology of the highly enriched anammox consortia used here and Candidatus Jettenia asiatica (J. asiatica) reached 99%. Results showed that low acetate (⩽30 mg/L) and propionate (⩽50 mg/L) concentration does not significantly influence ammonium oxidation. Higher acetate/propionate concentrations caused decrease of ammonium removal. A level of acetate no more than 240 mg/L caused the decrease of ammonium consumption rate by 33%, and 29% for propionate with (<400 mg/L). J. asiatica showed higher adaptability to propionate stress than acetate. Real-time quantitative PCR (qPCR) results reveal that anammox bacteria J. asiatica are capable of growing at the present of low-concentration acetate (⩽120 mg/L)/propionate (⩽200 mg/L). The anammox hzo gene concentrations reached to round 0.5 × 108–1.0 × 108 copies/ml after 36 days cultivation with C2/C3 fatty acid. However, there is no superiority for J. asiatica consortia to grow under organotrophic conditions compared to autotrophic ones.

Microbial Biofilms Formed in a Laboratory-Scale Anammox Bioreactor with Flexible Brush Carrier

This study is focused on investigation of biofilms formed in an anaerobic laboratory-scale bioreactor fed with medium for anammox bacteria oxidizing ammonia with nitrite. The mixed culture of anammox bacteria was enriched from the microbial community that sampled from the activated sludge of a denitrifying reactor at a wastewater treatment station located in the Sochi region, Russia. This community forms biofilms on the surface of the flexible polymer brush carriers, which are used for biomass immobilization in both laboratory and full-scale bioreactors. Anammox bacteria were discovered in the activated sludge community. The anammox community was enriched by incubation in an up-flow laboratory-scale anaerobic bioreactor with a flexible brush carrier. In the course of ~3 years, the loading rate of nitrogen substrates (ammonium and nitrite) increased from 100 to 5000 mg N L-1 day-1. The concentration of the substrates in the upper part of the reactor was 40 times less than in the influent. The pH values were 7.5 at the bottom and up to 9 in the upper part up of the reactor. Biofilms of two types developed in the reactor. Bunches of irregular spherical granules formed on the carrier filaments, while films of irregular thickness containing submerged spherical granules were formed on the walls of reactor. The anammox population was found to consist of at least three active species: a new strain of Candidatus “Jettenia asiatica” named “strain ecos” and two species of the genus Candidatus “Brocadia”. Other types of bacteria found in the community, including members of phylum Chloroflexi, were presumably involved in biofilm spatial organization.

Distribution and characterization of anammox in a swine wastewater activated sludge facility

Anaerobic ammonium oxidation (anammox) is a novel biological nitrogen removal process that oxidizes NH4(+) to N2 with NO2(-) as an electron acceptor. The purpose of this study was to examine the potential activity and characteristics of anammox in a conventional swine wastewater treatment facility, which uses an activated sludge system consisting of three cascade aeration tanks equipped with ceramic support material. Anammox activity was estimated by a (15)N tracer assay method and was detected in all the sludge and biofilm samples in each aeration tank. Biofilm taken from the third aeration tank, in which the dissolved oxygen concentration was 7.5 mg/L and the wastewater included a high concentration of NO3(-), showed by far the highest anammox activity. A clone library analysis showed the existence of anammox bacteria closely related to 'Candidatus Jettenia asiatica' and 'Ca. Brocadia caroliniensis'. The optimum conditions for anammox activity were a pH of 6.7-7.2, a temperature of 35 °C, a NO2(-) concentration of 10 mmol/L or less, and an NH4(+) concentration of 32 mmol/L or less.

Enrichment of an anammox bacterial community from a flooded paddy soil

This study describes the enrichment of anammox bacteria in a column simulating oxygen limited flooded paddy soils, which are important man-made ecosystems that receive substantial amounts of fixed nitrogen. The upper 50 cm of the paddy soil, containing a high amount of ammonium [1.6-10.4 mmol N kg (dry weight)(-1)], was selected as the inoculum for anammox enrichment. After 18 months of incubation with freshwater from the paddy soil ecosystem, the enrichment culture consumed approximately 4 mmol ammonium l(-1) day(-1) and 5 mmol nitrite l(-1) day(-1). The maximum specific anammox activity of the culture was 35.7 μmol N g (dry weight)(-1) h(-1). Fluorescence in situ hybridization indicated that anammox cells constituted 50% ± 10% of the enrichment culture. The phylogenetic analyses of 16S rRNA and the diagnostic hydrazine synthase (hzsA) genes showed that two dominant anammox species were enriched from paddy soil. The enriched Candidatus Anammoxoglobus-like organisms showed a 16S rRNA gene similarity of 97.5-99.2% to Candidatus Anammoxoglobus propionicus and the Candidatus Jettenia-like organisms showed 92.1-93.1% 16S rRNA gene identity to Candidatus Jettenia asiatica. Real-time quantitative PCR of hzsA gene suggested that up to 10(10) copies g (dry weight)(-1) of soil anammox bacteria were present in the enrichment culture.