• Journal of Korean Society on Water Environment
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• v.29 no.6
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• pp.782-789
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• 2013

Enhanced biological phosphorus removal (EBPR) behavior and microbial characteristics in the anaerobic-aerobic SBR (PAO SBR) and the anaerobic-anoxic SBR (DPAO SBR) were examined in this research. For 392 days of operation, both SBRs have exhibited a good EBPR (or denitrifying EBPR) performance. $P_{release}/P_{influent}$ ratio was highest in both reactors after the stabilization, while the efficiency of phosphorus removal was decreased since the sludge granulation has been visually observed within the reactor. The comparative analysis of Pyrosequencing-based microbial population between PAO and DPAO sludges showed indirectly that Dechloromonas spp. could utilize $O_2$ and $NO_3{^-}-N$ as an electron acceptor and Accumulibacter phosphatis use only $O_2$ in EBPR system. Also, we concluded that Thauera spp. as a denitrifier contribute significantly to the anoxic phosphorus removal in the DPAO system.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.105-108
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• 2000

Enhanced biological phosphorus removal (EBPR) is not always successfully achieved by anaerobic/aerobic operation. It has been reported that the EBPR deterioration was caused by the outgrowth of glycogen-accumulating organisms (GAO) over polyphosphate-accumulating organisms (PAO). It was found that pHcould be a tool which might induce the success of EBPR in a sequencing batch reactor (SBR) supplied with acetate. When the pH of anaerobic phase was controlled at 7.0, the operation resulted in failure of EBPR. However, when the pH of anaerobic phase increased up to 8.4, complete EBPR was achieved. We explained the mechanism of pH effect on the competition between GAO and PAO with experimental results and previously proposed biochemical models.

• Journal of Environmental Science International
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• v.19 no.4
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• pp.483-490
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• 2010

The purpose of this study is to investigate the effect of influent phosphorus concentration on the nitrogen and phosphorus removal in sequencing batch reactor(SBR) and sequencing batch biofilm reactors(SBBRs) in order to recover the enhanced biological phosphorus removal (EBPR) capacity at the sludge of the deterioration of EBPR capacity. In SBBRs, comparing to SBR, the organic removal was occurred actively at the 1 st non-aeration period because of the active phosphorus release at this period. However, the variation of TOC removal according to the decrease of influent phosphorus concentration was not clearly shown both in SBR and SBBRs. In case of SBR losing EBPR capacity, the EBPR capacity was not recovered by the decrease of the influent phosphorus concentration from 7.5 mg/L to 0.9 mg/L. The nitrogen removal increased by the decrease of influent phosphorus concentration both in SBR and SBBRs.

• Biotechnology and Bioprocess Engineering:BBE
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• v.7 no.6
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• pp.335-339
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• 2002

Laboratory experiments were conducted using pure cultures of Acinetobacter under an-aerobic/aerobic cyclic conditions to explain the release and uptake of soluble phosphate in an activated sludge process showing enhanced biological phosphate removal (EBPR). Under anaerobic/aerobic cyclic conditions in a Sequencing Batch Reactor (SBR), COD uptake concurrent with soluble phosphate release by Acinetobacter was not significant during the anaerobic periods, indicating that EBPR would not be established in pure cultures. However Acinetobacter cells accumulated higher phosphate content (5.2%) in SBR than that obtained (4.3%) from batch experiments. These results suggest that Acinetobacter sp. may not follow the proposed pattern of behavior of poly-P bacteria in EBPR activated sludge Plants.

• Journal of Microbiology and Biotechnology
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• v.14 no.4
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• pp.730-736
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• 2004

This study aims at characterizing the bacteriophages isolated from activated sludge performing enhanced biological phosphorous removal (EBPR) to understand the interactions between the phage-host system and bacterial community. Sixteen bacterial isolates (E1-E16) were isolated as host bacterial strains from EBPR activated sludge for phage isolation. Forty bacteriophages based on their plaque sizes (2 plaques on E4, 4 on E8, 11 on E10, 5 on E14, 18 on E16) were obtained from filtered supernatant of the EBPR activated sludge. Each bacteriophage did not make any plaque on bacterial strains tested in this study except on its own host bacterial strain, respectively, indicating that the bacteriophages are with narrow host specificity. However, fourteen of the forty bacteriophages obtained in this study lost their virulent ability even on their own host bacteria. All of the lytic phages showed similar one-step growth patterns and had long latent period (about 9 hours) to reproduce their phage particles in their host bacterial cells. On the other hand, their probable burst sizes (6 to 48 per host cell) were large enough to actively lyse their host bacterial cells. Therefore, it could be implied that bacteriophages are also important members of the microbial community in EBPR activated sludge, and lytic phages directly decrease the population size of their host bacterial groups in EBPR activated sludge by lysis.

• Journal of Microbiology and Biotechnology
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• v.18 no.7
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• pp.1290-1297
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• 2008

To investigate the diversities of Accumulibacter phosphatis and its polyhydroxyalkanoate (PHA) synthase gene (phaC) in enhanced biological phosphorus removal (EBPR) sludge, an acetate-fed sequencing batch reactor was operated. Analysis of microbial communities using fluorescence in situ hybridization and 16S rRNA gene clone libraries showed that the population of Accumulibacter phosphatis in the EBPR sludge comprised more than 50% of total bacteria, and was clearly divided into two subgroups with about 97.5% sequence identity of the 16S rRNA genes. PAO phaC primers targeting the phaC genes of Accumulibacter phosphatis were designed and applied to retrieve fragments of putative phaC homologs of Accumulibacter phosphatis from EBPR sludge. PAO phaC primers targeting $G_{1PAO},\;G_{2PAO},\;and\;G_{3PAO}$ groups produced PCR amplicons successfully; the resulting sequences of the phaC gene homologs were diverse, and were distantly related to metagenomic phaC sequences of Accumulibacter phosphatis with 75-98% DNA sequence identities. Degenerate NPAO (non-PAO) phaC primers targeting phaC genes of non-Accumulibacter phosphatis bacteria were also designed and applied to the EBPR sludge. Twenty-four phaC homologs retrieved from NPAO phaC primers were different from the phaC gene homologs derived from Accumulibacter phosphatis, which suggests that the PAO phaC primers were specific for the amplification of phaC gene homologs of Accumulibacter phosphatis, and the putative phaC gene homologs by PAO phaC primers were derived from Accumulibacter phosphatis in the EBPR sludge. Among 24 phaC homologs, a phaC homolog (GINPAO-2), which was dominant in the NPAO phaC clone library, showed the strongest signal in slot hybridization and shared approximately 60% nucleotide identity with the $G_{4PAO}$ group of Accumulibacter phosphatis, which suggests that GINPAO-2 might be derived from Accumulibacter phosphatis. In conclusion, analyses of the 16S rRNA and phaC genes showed that Accumulibacter phosphatis might be phylogenetically and metabolically diverse.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2004.11a
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• pp.90-91
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• 2004

한 시스템 내에 GAOs와 PAOs의 공존은 몇몇의 kinetic과 화학양론적 함축을 가지고 있다. 이는 유기물질 획득율의 측면에서 PAOs가 혐기성 단계에서 GAOs보다 kinetic적으로 유리하다고 제안되고 혐기조건에서 GAOs와 PAOs는 이용 가능한 기질에 대해 경쟁한다. PAOs에 있는 저장과는 달리, GAOs에서 glycogen의 생성은 과잉 인을 요구하지 않는다. 그러므로 GAOs는 성장에 필요한 이상의 인을 섭취하지 않는다. 결과적으로 EBPR 시스템의 방해요인이 될 수 있다. 이용 가능한 기질의 농도는 PAOs와 GAOs의 경쟁구도에 상당한 영향을 미치는 이는 전체 EBPR 시스템 내에서 인 제거 효율에 영향을 미칠 수 있다.

• Journal of Korean Society on Water Environment
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• v.29 no.4
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• pp.459-465
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• 2013

A sequencing batch reactor was operated under different pH conditions to see the influence of pH to microbial community in enhanced biological phosphorus removal (EBPR) systems. Long term influences of different steady-state pH conditions on the microbial community composition were evaluated by polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) and fluorescence in situ hybridization (FISH). The shift in populations from polyphosphate-accumulating organisms (PAOs) to Alphaproteobacteria was observed when pH was changed from 7.5 to 7.0. Alphaproteobacteria with the typical morphological traits of tetrad-forming organisms (TFOs) eventually became dominant members. The alphaproteobacterial TFOs were the phenotype expected for glycogen-accumulating organisms (GAOs), which accumulate large amount of glycogen into the cell. The results strongly suggested that low operational pH condition encourages the appearance of the GAOs in EBPR process, significantly reducing the EBPR capacity.

• Journal of Microbiology and Biotechnology
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• v.13 no.3
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• pp.385-393
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• 2003

Microbial communities were analyzed in an anaerobic/aerobic sequencing batch reactor (SBR) fed with glucose as a sole carbon source. Scanning electron microscopy (SEM) showed that tetrad or cuboidal packet bacteria dominated the microbial sludge. Quinone, slot hybridization, and 165 rRNA gene sequencing analyses showed that the Proteobacteria beta subclass and the Actinobacteria group were the main microbial species in the SBR sludge. However, according to transmission electron microscopy (TEM), the packet bacteria did not contain polyphosphate granules or glycogen inclusions, but only separate coccus-shaped bacteria contained these, suggesting that coccus-shaped bacteria accumulated polyphosphate directly and the packet bacteria played other role in the enhanced biological phosphorus removal (EBPR). Based on previous reports, the Actinobacteria group and the Proteobacteria beta subclass were very likely responsible for acid formation and polyphosphate accumulation, respectively, and their cooperation achieved the EBPR in the SBR operation which was supplied with glucose.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.5
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• pp.939-947
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• 2000

Enhanced biological phosphorus removal (EBPR) was performed in an anaerobic/aerobic sequencing batch reactor (SBR). Influent was a synthetic wastewater based on acetate as a carbon source. The sludge age and hydraulic retention time were kept at 10 days and 16 hrs, respectively, Phosphate release during the anaerobic period and phosphate uptake in aerobic period were increased gradually with time. and after about 200 days, steady-state operation could be achieved with complete removal of influent phosphate. Number distribution of microbial community in the sludge performing EBPR was investigated during the steady state operation. 17 rRNA targeted oligonucleotide probes were designed and slot hybridization technique was used to determine the number distribution of each microorganism. In the acetate fed SBR, rRNA belonging to the beta subclass of proteobacteria was the most dominant in total rRNA and rRNA matching to CTE probe was the second, rRNAs of Acinetobacter, Aeromonas and Pseudomonas, which are usually thought as phosphorus accumulating organisms in EBPR processes, constituted less than 10% of total rRNA. From this community analysis, it was inferred that microorganisms belong to the beta subclass of proteobacteia (BET) and CTE such as Rhodocyclus group were important in biological phosphorus removal. Therefore, the role of Acinetobacter, Aeromonas and Pseudomonas in the EBPR might have been overestimated.