title: Polyhydroxyalkanoate (PHA) accumulation potential and PHA-accumulating microbial communities in various activated sludge processes of municipal wastewater treatment plants.
abstract: OBJECTIVE
  To clarify the polyhydroxyalkanoate (PHA) accumulation potential and the PHA-accumulating microbial community structure in activated sludge in municipal wastewater treatment plants (WWTPs) and to identify their influential factors.
  
  
  RESULTS
  Nine activated sludge samples were collected from municipal WWTPs employing various biological treatment processes. In acetate-fed 24-h batch experiments under aerobic and nitrogen- and phosphorus-limited conditions, polyhydroxybutyrate (PHB) content of activated sludge increased from 0-1·3 wt% to 7·9-24 wt%, with PHB yields of 0·22-0·50 C-mol 3-hydroxybutyrate (C-mol acetate)(-1). Microbial community analyses found that activated sludge samples that accumulated >20 wt% of PHB after 24-h PHA accumulation experiments had >5·0 × 10(8) copies g(-1)-mixed liquor-suspended solid of phaC genes.
  
  
  CONCLUSIONS
  Results indicated that (i) activated sludge in municipal WWTPs can accumulate up to approx. 20 wt% of PHA without enrichment processes, (ii) PHA accumulation potential of activated sludge varied depending on the operational conditions (treatment processes) of WWTPs, and (iii) phaC gene number can provide a simple indication of PHA accumulation potential.
  
  
  CONCLUSIONS
  This is the first study to compare the PHA accumulation potential and PHA-accumulating microbial communities in activated sludge of various treatment processes. Our findings may be useful for enhancing the resource recovery potential of wastewater treatment systems.
authors.affiliation: Division of Sustainable Energy and Environmental Engineering, Osaka University, Suita, Osaka, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Sakai
authors.forename: S
authors.initials: S
authors.lastname: Miyake
authors.forename: K
authors.initials: K
authors.lastname: Iwama
authors.forename: D
authors.initials: D
authors.lastname: Inoue
authors.forename: S
authors.initials: S
authors.lastname: Soda
authors.forename: M
authors.initials: M
authors.lastname: Ike
mesh_terms: D001419:Bacteria / Q000302:isolation & purification / Q000378:metabolism; D054813:Polyhydroxyalkanoates / Q000032:analysis* / Q000378:metabolism; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology*; D064091:Waste Disposal Facilities
chemical_list: D054813:Polyhydroxyalkanoates; D012722:Sewage
keywords: activated sludge; microbial community analysis; phaC gene; polyhydroxyalkanoate accumulation potential; polyhydroxyalkanoate-accumulating organism