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In this study, the abundance and sequences of amoA genes of ammonia-oxidizing archaea (AOA) and bacteria (AOB) were determined in seven wastewater treatment plants (WWTPs) whose ammonium concentrations in influent and effluent wastewaters varied considerably (5.6-422.3 mgN l(-1) and 0.2-29.2 mgN l(-1), respectively). Quantitative real-time PCR showed that(More)
We investigated ammonia-oxidizing bacteria in activated sludge collected from 12 sewage treatment systems, whose ammonia removal and treatment processes differed, during three different seasons. We used real-time PCR quantification to reveal total bacterial numbers and total ammonia oxidizer numbers, and used specific PCR followed by denaturing gel gradient(More)
The contribution of ammonia-oxidizing archaea (AOA) to nitrogen removal in wastewater treatment plants (WWTPs) remains unknown. This study investigated the abundance of archaeal (AOA) and bacterial (ammonia-oxidizing bacteria (AOB)) amoA genes in eight of Bangkok's municipal WWTPs. AOA amoA genes (3.28 × 10(7) ± 1.74 × 10(7)-2.23 × 10(11) ± 1.92 × 10(11)(More)
This study carried out quantification of ammonia-oxidizing bacteria (AOB) populations in 12 full-scale sewage activated sludge systems that were different in ammonia removals and treatment processes during three different seasons. Experiment was divided into 3 parts: 1) analysis of AOB communities by PCR-DGGE-cloning-sequencing of 16S rRNA genes; 2)(More)
In this study, sludge was taken from a municipal wastewater treatment plant that contained a nearly equal number of archaeal amoA genes (5.70 × 10⁶ ± 3.30 × 10⁵ copies mg sludge⁻¹) to bacterial amoA genes (8.60 × 10⁶ ± 7.64 × 10⁵ copies mg sludge⁻¹) and enriched in three continuous-flow reactors receiving an inorganic medium containing different ammonium(More)
In this study, four real-time polymerase chain reaction (PCR) primer sets were developed for the 16S rRNA genes of specific ammonia-oxidizing bacteria (AOB) found in activated sludge of sewage treatment systems. The primer sets target two of several sequence types of the Nitrosomonas oligotropha cluster, members within the Nitrosomonas communis cluster, and(More)
This study investigated the effects of ammonium and nitrite on ammonia-oxidizing bacteria (AOB) from an activated sludge process in laboratory-scale continuous-flow reactors. AOB communities were analyzed using specific PCR followed by denaturing gel gradient electrophoresis, cloning and sequencing of the 16S rRNA gene, and AOB populations were quantified(More)
Recent evidence from natural environments suggests that in addition to ammonia-oxidizing bacteria, ammonia-oxidizing archaea (AOA) affiliated with Thaumarcheota, a new phylum of the domain Archaea, also oxidize ammonia to nitrite and thus participate in the global nitrogen cycle. Besides natural environments, modern data indicate the presence of(More)
AIMS The aim of this work was to enrich stable mixed cultures from atrazine-contaminated soil. The cultures were examined for their atrazine biodegradation efficiencies in comparison with J14a, a known atrazine-degrading strain of Agrobacterium radiobacter. The cultures were also characterized to identify community structure and bacterial species present.(More)
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(More)