title: Fractionation of microbial populations in a PHA accumulating mixed culture and associated PHA content and composition.
abstract: The uniformity of PHA composition and content across groups of organisms in mixed cultures was considered. An activated sludge microbial community, with an average PHA content of 20wt%, was fractioned by Percoll assisted buoyant density separation. The microbial community in the two principal fractions was characterised using amplicon pyrosequencing. While organisms were common to both fractions, the relative abundances of species were found to be different between the two fractions. The average PHA content in one of the fractions was found to be higher (24wt%) than the other (16wt%); separation was considered to be in part driven by the density difference associated with PHA content, but also by other factors such as cell dimension and cellular morphology. But while differences in PHA content were observed, the PHA composition in both fractions was found to be approximately the same (43-44mol% HV), which shows that distinct groups of microbial populations within mixed cultures may generate PHA with similar average copolymer composition.
authors.affiliation: School of Chemical Engineering, The University of Queensland, Brisbane 4072, QLD, Australia.
authors.forename: Om Murugan
authors.initials: OM
authors.lastname: Janarthanan
authors.affiliation: Advanced Water Management Centre, The University of Queensland, Brisbane 4072, QLD, Australia.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yu
authors.affiliation: School of Chemical Engineering, The University of Queensland, Brisbane 4072, QLD, Australia.
authors.forename: Bronwyn
authors.initials: B
authors.lastname: Laycock
authors.affiliation: AnoxKaldnes AB, Klosterängsvägen 11A, SE-226 47 Lund, Sweden.
authors.forename: Alan
authors.initials: A
authors.lastname: Werker
authors.affiliation: School of Chemical Engineering, The University of Queensland, Brisbane 4072, QLD, Australia. Electronic address: s.pratt@uq.edu.au.
authors.forename: Steven
authors.initials: S
authors.lastname: Pratt
mesh_terms: D044822:Biodiversity; D005591:Chemical Fractionation; D005285:Fermentation; D064307:Microbiota; D054813:Polyhydroxyalkanoates / Q000737:chemistry* / Q000378:metabolism*; D012722:Sewage / Q000737:chemistry / Q000382:microbiology
chemical_list: D054813:Polyhydroxyalkanoates; D012722:Sewage
keywords: Buoyant density gradient centrifugation; Mixed cultures; PHA; Polyhydroxyalkanoates; Pyrosequencing