title: Calcium effect on the metabolic pathway of phosphorus accumulating organisms in enhanced biological phosphorus removal systems.
abstract: Phosphorus accumulating organisms (PAOs) have been found to act as glycogen-accumulating organisms (GAOs) under certain conditions, thus, the deterioration in the performance of enhanced biological phosphorus removal systems is not always attributed to the proliferation of GAOs. In this work, the effects of calcium on the metabolic pathway of PAOs were explored. It was found that when the influent Ca(2+) concentration was elevated, the tendency and extent of extracellular calcium phosphate precipitation increased, and the intracellular inert Ca-bound polyphosphate was synthesized, while the microbial population remained almost unchanged. The changes in the ratios of phosphorus released/acetate uptaken, the glycogen degraded/acetate uptaken and the poly-β-hydroxyalkanoates synthesized/acetate uptaken during the anaerobic period confirm that, as the influent Ca(2+) concentration was increased, the polyphosphate-accumulating metabolism was partially shifted to the glycogen-accumulating metabolism. At an influent Ca(2+) around 50 mg/L, in addition to the extracellular calcium phosphate precipitation, the intracellular inert Ca-bound polyphosphate synthesis might also be involved in the metabolic change of PAOs. The results of the present work would be beneficial to better understand the biochemical metabolism of PAOs in enhanced biological phosphorus removal systems.
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei, 230026, China; Institute of Materials, China Academy of Engineering Physics, Mianyang, Sichuan, 621907, China.
authors.forename: Hai-Ling
authors.initials: HL
authors.lastname: Zhang
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei, 230026, China. Electronic address: gpsheng@ustc.edu.cn.
authors.forename: Guo-Ping
authors.initials: GP
authors.lastname: Sheng
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei, 230026, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Fang
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei, 230026, China; Institute of Materials, China Academy of Engineering Physics, Mianyang, Sichuan, 621907, China.
authors.forename: Yong-Peng
authors.initials: YP
authors.lastname: Wang
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei, 230026, China.
authors.forename: Cai-Yun
authors.initials: CY
authors.lastname: Fang
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei, 230026, China.
authors.forename: Li-Min
authors.initials: LM
authors.lastname: Shao
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei, 230026, China. Electronic address: hqyu@ustc.edu.cn.
authors.forename: Han-Qing
authors.initials: HQ
authors.lastname: Yu
mesh_terms: D019149:Bioreactors; D002118:Calcium / Q000378:metabolism*; D006003:Glycogen / Q000378:metabolism; D010758:Phosphorus / Q000378:metabolism*; D012722:Sewage / Q000382:microbiology; D018508:Water Purification
chemical_list: D012722:Sewage; D010758:Phosphorus; D006003:Glycogen; D002118:Calcium
keywords: Glycogen-accumulating metabolism (GAM); Granular sludge; Metabolic pathway; Phosphorus accumulating organisms (PAOs); Polyphosphate-accumulating metabolism (PAM)