title: Changes in respiratory quinone profiles of enhanced biological phosphorus removal activated sludge under different influent phosphorus/carbon ratio conditions.
abstract: Changes in the microbial community of an enhanced biological phosphorus removal (EBPR) activated sludge system under different influent phosphorus/carbon (P/C) ratio conditions were investigated through evaluation of population respiratory quinone profiles. A total of 13 types of respiratory quinone homologs consisting of 3 types of ubiquinones (UQ) and 10 types of menaquinones (MK) were identified in this study. The dominant quinones were UQ-8 and MK-7 throughout the operational period. A higher P/C ratio (0.1) in the influent stimulated an increase in the mole fractions of UQ-8, MK-7, MK-8(H(4)), MK-9(H(4)) and MK-8(H(8)), suggesting that actinobacterial polyphosphate-accumulating organisms (PAO) containing partially hydrogenated MK, mainly MK-8(H(4)), were contributing to EBPR. However, when the P/C ratio gradually decreased from 0.1 to 0.01, the mole fractions of UQ-8 increased from 0.46 to 0.58, while MK-7, MK-8(H(2)), MK-8(H(4)), MK-9(H(4)), MK-8(H(8)) and MK-9(H(6)) markedly decreased. These changes in the respiratory quinone profiles suggest that glycogen-accumulating organisms corresponding to some Gammaproteobacteria had become dominant populations with a decrease in actinobacterial PAO. On the other hand, increasing abruptly the P/C ratio to 0.1 further caused an increase in the mole fraction of UQ-8, indicating that Rhodocyclus-related organisms were important PAO.
authors.affiliation: Department of Pharmacy, La Trobe University, Bendigo 3550, Australia. j.ahn@latrobe.edu.au
authors.forename: Johwan
authors.initials: J
authors.lastname: Ahn
authors.forename: Mikyung
authors.initials: M
authors.lastname: Lee
authors.forename: Hyukku
authors.initials: H
authors.lastname: Kwon
mesh_terms: D001673:Biodegradation, Environmental; D019149:Bioreactors / Q000382:microbiology*; D002244:Carbon / Q000378:metabolism*; D018929:Cell Culture Techniques / Q000379:methods*; D020563:Gammaproteobacteria / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D010758:Phosphorus / Q000378:metabolism*; D011809:Quinones / Q000378:metabolism*; D012722:Sewage / Q000382:microbiology*
chemical_list: D011809:Quinones; D012722:Sewage; D010758:Phosphorus; D002244:Carbon; D010100:Oxygen