Jettenia Asiatica Research Articles

Co-occurrence and distribution of nitrite-dependent anaerobic ammonium and methane-oxidizing bacteria in a paddy soil

The anaerobic ammonium-oxidizing (anammox) and nitrite-dependent anaerobic methane-oxidizing (n-damo) bacteria in a paddy soil core (0-100 cm) were investigated with newly designed primers targeting the hydrazine synthase β-subunit (hzsB) of anammox bacteria and the recently published primers targeting the pmoA and 16S rRNA genes of n-damo bacteria. The hzsB gene was identified as a proper biomarker to explore the anammox bacterial biodiversity and abundance in soil. The anammox bacteria were present throughout the soil core with the highest abundance of 2.7 × 10(6) hzsB copies g(-1) dry soil at 40-50 cm and were not detectable below 70 cm. Sequences related to at least three species of known anammox bacteria, 'Brocadia anammoxidans', 'Brocadia fulgida', and 'Jettenia asiatica' were detected. By combining the analysis of pmoA and 16S rRNA genes, the n-damo bacteria were observed to be present in 30-70 cm with abundance from 6.5 × 10(3) (60-70 cm) to 7.5 × 10(4) (30-40 cm) copies g(-1) dry soil. The pmoA sequences retrieved from different depths closely related to each other and formed a unique clade. Our results showed that anammox and n-damo bacteria co-occurred in the paddy soil. Both of them were abundant in deep layers (30-60 cm) and the community structures changed along depths in the soil core.

Inhibitory effects of free ammonia on Anammox bacteria

Anammox bacteria can effectively treat high ammonia and nitrite concentrations under anoxic environments. However, the presence of high ammonia and nitrite concentrations may cause free ammonia and nitrous acid inhibition at high pH and temperature environments. In this study, the inhibitory effect of free ammonia on Anammox bacteria was investigated in a lab-scale upflow fixed-bed reactor with Kaldnes biofilm carriers. Results of continuous operation showed that inhibition was not observed in the Anammox reactor when the free ammonia concentration gradually increased up to 150mg/L. However, Anammox activity suddenly dropped to 10 % when the free ammonia concentration reached to 190mg/L. Nevertheless, high influent ammonia and nitrite concentrations up to 1,500 and 500mg/L, respectively, did not noticeably inhibit the Anammox activity. Gradually decreasing Anammox activity was also supported by fluorescent in situ hybridization (FISH) analysis. FISH and 16S rRNA gene analysis results revealed that main Anammox organisms were phylogenetically related to Candidatus Kuenenia stuttgartiensis, Candidatus Jettenia asiatica and Candidatus Brocadia anammoxidans.

Metagenome Analysis of a Complex Community Reveals the Metabolic Blueprint of Anammox Bacterium “Candidatus Jettenia asiatica”

Anaerobic ammonium-oxidizing (anammox) bacteria are key players in the global nitrogen cycle and responsible for significant global nitrogen loss. Moreover, the anammox process is widely implemented for nitrogen removal from wastewaters as a cost-effective and environment-friendly alternative to conventional nitrification-denitrification systems. Currently, five genera of anammox bacteria have been identified, together forming a deep-branching order in the Planctomycetes-Verrucomicrobium-Chlamydiae superphylum. Members of all genera have been detected in wastewater treatment plants and have been enriched in lab-scale bioreactors, but genome information is not yet available for all genera. Here we report the metagenomic analysis of a granular sludge anammox reactor dominated (∼50%) by “Candidatus Jettenia asiatica.” The metagenome was sequenced using both Illumina and 454 pyrosequencing. After de novo assembly 37,432 contigs with an average length of 571 nt were obtained. The contigs were then analyzed by BLASTx searches against the protein sequences of “Candidatus Kuenenia stuttgartiensis” and a set of 25 genes essential in anammox metabolism were detected. Additionally all reads were mapped to the genome of an anammox strain KSU-1 and de novo assembly was performed again using the reads that could be mapped on KSU-1. Using this approach, a gene encoding copper-containing nitrite reductase NirK was identified in the genome, instead of cytochrome cd1-type nitrite reductase (NirS, present in “Ca. Kuenenia stuttgartiensis” and “Ca. Scalindua profunda”). Finally, the community composition was investigated through MetaCluster analysis, 16S rRNA gene analysis and read mapping, which showed the presence of other important community members such as aerobic ammonia-oxidizing bacteria, methanogens, and the denitrifying methanotroph “Ca. Methylomirabilis oxyfera”, indicating a possible active methane and nitrogen cycle in the bioreactor under the prevailing operational conditions.

Bacterial biodiversity from an anaerobic up flow bioreactor with ANAMMOX activity inoculated with swine sludge

The present study aimed to describe the bacterial community present at an anaerobic up flow bioreactor with ANAMMOX activity, inoculated with the sludge from the anaerobic pond of a swine slurry treatment system. The description was based on the molecular DNA techniques using primers for amplification of complete 16S rRNA gene and also new primers to amplify smaller fragments from 16S rRNA. During the bioreactor operation time, the bacterial community changed significantly, increasing the nitrogen removal efficiency, reaching after 500 days a removal rate of 94%. The complete PCR amplification of 16S rRNA gene generated 17 clones, where three presented similarity with Candidatus Jettenia asiatica (97%), twelve with Janthinobacterium (99%) and two with uncultured clones. The PCR amplification of 436 base pairs had generated 12 clones, of which eight presented 96-100% similarity with Candidatus Anammoxoglobus propionicus, Planctomycete KSU-1 and one with Pseudomonas sp. (99%) and three with uncultured clones.

Anammox bacteria community and nitrogen removal in a strip-like wetland in the riparian zone

A strip-like wetland was constructed in the riparian zone for investigation of ammonium nitrogen (NH3-N) removal in the Peach River. An inner zeolite layer was set in the wetland to adsorb NH3-N and further to remove total nitrogen (TN). An oxygen-deficient condition with dissolved oxygen of 0.87–1.60 mg L−1 was observed in the zeolite layer, which benefits anaerobic ammonium oxidation (anammox) bacteria survival. The community structure of anammox bacteria was analyzed in the zeolite layer. The analysis shows that the anammox bacterial sequences are grouped into three known distinct clusters: Candidatus Brocadia fulgida, Candidatus Brocadia anammoxidans and Candidatus Jettenia asiatica. The intensified test driven by artificial pumping shows that average removal rates of NH3-N and TN are 41.6 mg m−3d−1 and 63.2 mg m−3d−1, respectively. The normal test driven by natural hydrodynamics also verifies that NH3-N removal mainly happens in the zeolite layer. Microbial mechanism of TN removal in the wetland involves both the autotrophic and heterotrophic process. These results suggest that the strip-like RW can be a cost-effective approach for NH3-N removal and can potentially be extended to similar rivers as no extra energy is required to maintain the wetland operation.

Diversity of ammonium‐oxidizing bacteria in a granular sludge anaerobic ammonium‐oxidizing (anammox) reactor

The ammonium-oxidizing microbial community was investigated in a granular sludge anaerobic ammonium-oxidizing (anammox) reactor that was operated for about 1 year with high anaerobic ammonium oxidation activity (up to 0.8 kg NH(4)(+)-N m(-3) day(-1)). A Planctomycetales-specific 16S rRNA gene library was constructed to analyse the diversity of the anaerobic ammonium-oxidizing bacteria (AnAOB). Most of the specifically amplified sequences (15/16) were similar to each other (> 99%) but were distantly related to all of the previously recognized sequences (< 94%), with the exception of an unclassified anammox-related clone, KSU-1 (98%). An ammonia monooxygenase (amoA) gene library was also analysed to investigate the diversity of 'aerobic' ammonium-oxidizing bacteria (AAOB) from the beta-Proteobacteria. Most of the amoA gene fragments (53/55) clustered in the Nitrosomonas europaea-Nitrosococcus mobilis group which has been reported to prevail under oxygen-limiting conditions. The quantitative results from real-time polymerase chain reaction (PCR) amplification showed that the dominant AnAOB comprised approximately 50% of the total bacterial 16S rRNA genes in the reactor, whereas the AAOB of beta-Proteobacteria represented only about 3%. A large fragment (4008 bp) of the rRNA gene cluster of the dominant AnAOB (AS-1) in this reactor sludge was sequenced and compared with sequences of other Planctomycetales including four anammox-related candidate genera. The partial sequence of hydrazine-oxidizing enzyme (hzo) of dominant AnAOB was also identified using new designed primers. Based on this analysis, we propose to tentatively name this new AnAOB Candidatus'Jettenia asiatica'.