Candidatus Accumulibacter,a prominent polyphosphate-accumulating organism(PAO)in wastewater treatment,plays a crucial role in enhanced biological phosphorus removal(EBPR).The genetic underpinnings of its polyphosphate...Candidatus Accumulibacter,a prominent polyphosphate-accumulating organism(PAO)in wastewater treatment,plays a crucial role in enhanced biological phosphorus removal(EBPR).The genetic underpinnings of its polyphosphate accumulation capabilities,however,remain largely unknown.Here,we conducted a comprehensive genomic analysis of Ca.Accumulibacter-PAOs and their relatives within the Rhodocyclaceae family,identifying 124 core genes acquired via horizontal gene transfer(HGT)at its least common ancestor.Metatranscriptomic analysis of an enrichment culture of Ca.Accumulibacter revealed active transcription of 44 of these genes during an EBPR cycle,notably including the polyphosphate kinase 2(PPK2)gene instead of the commonly recognized polyphosphate kinase 1(PPK1)gene.Intriguingly,the phosphate regulon(Pho)genes showed minimal transcriptions,pointing to a distinctive fact of Pho dysregulation,where PhoU,the phosphate signaling complex protein,was not regulating the high-affinity phosphate transport(Pst)system,resulting in continuous phosphate uptake.To prevent phosphate toxicity,Ca.Accumulibacter utilized the laterally acquired PPK2 to condense phosphate into polyphosphate,resulting in the polyphosphate-accumulating feature.This study provides novel insights into the evolutionary emergence of the polyphosphate-accumulating trait in Ca.Accumulibacter,offering potential advancements in understanding the PAO phenotype in the EBPR process.展开更多
Candidatus Accumulibacter has been identified as dominant polyphosphate-accumulating organisms（PAOs） in enhanced biological phosphorus（P） removal（EBPR） from wastewater.This study revealed the relevance of commun...Candidatus Accumulibacter has been identified as dominant polyphosphate-accumulating organisms（PAOs） in enhanced biological phosphorus（P） removal（EBPR） from wastewater.This study revealed the relevance of community structure, abundance and seasonal population dynamics of Candidatus Accumulibacter to process operation of wastewater treatment plants（WWTPs） in China using ppk1 gene as phylogenetic marker. All sludge samples had properties of denitrifying P removal using nitrate as an electron acceptor.Accumulibacter abundance in the anaerobic-anoxic-oxic（A^2O） process was the highest（26%of total bacteria）, and higher in winter than in summer with a better EBPR performance.Type-II was the dominant Accumulibacter in all processes, and type-I accounted for a small proportion of total Accumulibacter. The abundance of Clade-IIC as the most dominant clade reached 2.59 × 10~9 cells/g MLSS and accounted for 87.3% of total Accumulibacter. Clade IIC mainly contributed to denitrifying P removal. Clades IIA, IIC and IID were found in all processes, while clade-IIF was only found in oxidation ditch process through phylogenetic analysis. High proportion of clade IID to total Accumulibacter led to poor performance of aerobic P-uptake in inverted A^2O process. Therefore, Accumulibacter clades in WWTPs were diverse, and EBPR performance was closely related to the clade-level community structures and abundances of Accumulibacter.展开更多
Currently,the most cost-effective and efficient method for phosphorus(P)removal from wastewater is enhanced biological P removal(EPBR)via polyphosphate-accumulating organisms(PAOs).This study integrates a literature r...Currently,the most cost-effective and efficient method for phosphorus(P)removal from wastewater is enhanced biological P removal(EPBR)via polyphosphate-accumulating organisms(PAOs).This study integrates a literature review with genomic analysis to uncover the phylogenetic and metabolic diversity of the relevant PAOs for wastewater treatment.The findings highlight significant differences in the metabolic capabilities of PAOs relevant to wastewater treatment.Notably,Candidatus Dechloromonas and Candidatus Accumulibacter can synthesize polyhydroxyalkanoates,possess specific enzymes for ATP production from polyphosphate,and have electrochemical transporters for acetate and C4-dicarboxylates.In contrast,Tetrasphaera,Candidatus Phosphoribacter,Knoellia,and Phycicoccus possess PolyP-glucokinase and electrochemical transporters for sugars/amino acids.Additionally,this review explores various detection methods for polyphosphate and PAOs in activated sludge wastewater treatment plants.Notably,FISH-Raman spectroscopy emerges as one of the most advanced detection techniques.Overall,this review provides critical insights into PAO research,underscoring the need for enhanced strategies in biological phosphorus removal.展开更多
We examined how long-term operation of anaerobic–oxic and anaerobic–anoxic sequencing batch reactors(SBRs) affects the enhanced biological phosphorus removal(EBPR)performance and sludge characteristics. The microbia...We examined how long-term operation of anaerobic–oxic and anaerobic–anoxic sequencing batch reactors(SBRs) affects the enhanced biological phosphorus removal(EBPR)performance and sludge characteristics. The microbial characteristics of phosphorus accumulating organism(PAO) and denitrifying PAO(DPAO) sludge were also analyzed through a quantitative analysis of microbial community structure. Compared with the initial stage of operation characterized by unstable EBPR, both PAO and DPAO SBR produced a stable EBPR performance after about 100-day operation. From day 200 days(DPAO SBR)and 250 days(PAO SBR) onward, sludge granulation was observed, and the average granule size of DPAO SBR was approximately 5 times larger than that of PAO SBR. The DPAO granular sludge contained mainly rod-type microbes, whereas the PAO granular sludge contained coccus-type microbes. Fluorescence in situ hybridization analysis revealed that a high ratio of Accumulibacter clade I was found only in DPAO SBR, revealing the important role of this organism in the denitrifying EBPR system. A pyrosequencing analysis showed that Accumulibacter phosphatis was present in PAO sludge at a high proportion of 6%,whereas it rarely observed in DPAO sludge. Dechloromonas was observed in both PAO sludge(3.3%) and DPAO sludge(3.2%), confirming that this organism can use both O_2 and NO_3^- as electron acceptors. Further, Thauera spp. was identified to have a new possibility as denitrifier capable of phosphorous uptake under anoxic condition.展开更多
基金supported by the National Natural Science Foundation of China(52270035 and 51808297)the Natural Science Foundation of Guangdong Province(2021A1515010494)+1 种基金the Guangzhou Key Research and Development Program(2023B03J1334)the Pearl River Talent Recruitment Program(2019QN01L125).
文摘Candidatus Accumulibacter,a prominent polyphosphate-accumulating organism(PAO)in wastewater treatment,plays a crucial role in enhanced biological phosphorus removal(EBPR).The genetic underpinnings of its polyphosphate accumulation capabilities,however,remain largely unknown.Here,we conducted a comprehensive genomic analysis of Ca.Accumulibacter-PAOs and their relatives within the Rhodocyclaceae family,identifying 124 core genes acquired via horizontal gene transfer(HGT)at its least common ancestor.Metatranscriptomic analysis of an enrichment culture of Ca.Accumulibacter revealed active transcription of 44 of these genes during an EBPR cycle,notably including the polyphosphate kinase 2(PPK2)gene instead of the commonly recognized polyphosphate kinase 1(PPK1)gene.Intriguingly,the phosphate regulon(Pho)genes showed minimal transcriptions,pointing to a distinctive fact of Pho dysregulation,where PhoU,the phosphate signaling complex protein,was not regulating the high-affinity phosphate transport(Pst)system,resulting in continuous phosphate uptake.To prevent phosphate toxicity,Ca.Accumulibacter utilized the laterally acquired PPK2 to condense phosphate into polyphosphate,resulting in the polyphosphate-accumulating feature.This study provides novel insights into the evolutionary emergence of the polyphosphate-accumulating trait in Ca.Accumulibacter,offering potential advancements in understanding the PAO phenotype in the EBPR process.
基金supported by the National Key Research and Development Programme of China (No. 2016YFC0401103)the Natural Science Foundation of China (No. 51578016)the Natural Science Foundation of Beijing (No. 8172014)
文摘Candidatus Accumulibacter has been identified as dominant polyphosphate-accumulating organisms（PAOs） in enhanced biological phosphorus（P） removal（EBPR） from wastewater.This study revealed the relevance of community structure, abundance and seasonal population dynamics of Candidatus Accumulibacter to process operation of wastewater treatment plants（WWTPs） in China using ppk1 gene as phylogenetic marker. All sludge samples had properties of denitrifying P removal using nitrate as an electron acceptor.Accumulibacter abundance in the anaerobic-anoxic-oxic（A^2O） process was the highest（26%of total bacteria）, and higher in winter than in summer with a better EBPR performance.Type-II was the dominant Accumulibacter in all processes, and type-I accounted for a small proportion of total Accumulibacter. The abundance of Clade-IIC as the most dominant clade reached 2.59 × 10~9 cells/g MLSS and accounted for 87.3% of total Accumulibacter. Clade IIC mainly contributed to denitrifying P removal. Clades IIA, IIC and IID were found in all processes, while clade-IIF was only found in oxidation ditch process through phylogenetic analysis. High proportion of clade IID to total Accumulibacter led to poor performance of aerobic P-uptake in inverted A^2O process. Therefore, Accumulibacter clades in WWTPs were diverse, and EBPR performance was closely related to the clade-level community structures and abundances of Accumulibacter.
基金supported by King Abdullah University of Science and Technology(KAUST).
文摘Currently,the most cost-effective and efficient method for phosphorus(P)removal from wastewater is enhanced biological P removal(EPBR)via polyphosphate-accumulating organisms(PAOs).This study integrates a literature review with genomic analysis to uncover the phylogenetic and metabolic diversity of the relevant PAOs for wastewater treatment.The findings highlight significant differences in the metabolic capabilities of PAOs relevant to wastewater treatment.Notably,Candidatus Dechloromonas and Candidatus Accumulibacter can synthesize polyhydroxyalkanoates,possess specific enzymes for ATP production from polyphosphate,and have electrochemical transporters for acetate and C4-dicarboxylates.In contrast,Tetrasphaera,Candidatus Phosphoribacter,Knoellia,and Phycicoccus possess PolyP-glucokinase and electrochemical transporters for sugars/amino acids.Additionally,this review explores various detection methods for polyphosphate and PAOs in activated sludge wastewater treatment plants.Notably,FISH-Raman spectroscopy emerges as one of the most advanced detection techniques.Overall,this review provides critical insights into PAO research,underscoring the need for enhanced strategies in biological phosphorus removal.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Education (No.NRF-2015R1D1A1A01061423)
文摘We examined how long-term operation of anaerobic–oxic and anaerobic–anoxic sequencing batch reactors(SBRs) affects the enhanced biological phosphorus removal(EBPR)performance and sludge characteristics. The microbial characteristics of phosphorus accumulating organism(PAO) and denitrifying PAO(DPAO) sludge were also analyzed through a quantitative analysis of microbial community structure. Compared with the initial stage of operation characterized by unstable EBPR, both PAO and DPAO SBR produced a stable EBPR performance after about 100-day operation. From day 200 days(DPAO SBR)and 250 days(PAO SBR) onward, sludge granulation was observed, and the average granule size of DPAO SBR was approximately 5 times larger than that of PAO SBR. The DPAO granular sludge contained mainly rod-type microbes, whereas the PAO granular sludge contained coccus-type microbes. Fluorescence in situ hybridization analysis revealed that a high ratio of Accumulibacter clade I was found only in DPAO SBR, revealing the important role of this organism in the denitrifying EBPR system. A pyrosequencing analysis showed that Accumulibacter phosphatis was present in PAO sludge at a high proportion of 6%,whereas it rarely observed in DPAO sludge. Dechloromonas was observed in both PAO sludge(3.3%) and DPAO sludge(3.2%), confirming that this organism can use both O_2 and NO_3^- as electron acceptors. Further, Thauera spp. was identified to have a new possibility as denitrifier capable of phosphorous uptake under anoxic condition.
