title: Polyhydroxybutyrate production by direct use of waste activated sludge in phosphorus-limited fed-batch culture.
abstract: Polyhydroxybutyrate (PHB) production directly by waste activated sludge (WAS) was investigated in aerobic fed-batch conditions using acetic acid as substrate. PHB production was induced by phosphorus limitation. WAS of different origin were tested with various degrees of phosphorus limitation and PHB contents of up to 70% (gCOD PHB/gCOD particulate) were obtained. This strategy showed the importance of maintaining cell growth for PHB production in order to increase PHB concentration and that the degree of phosphorus limitation has a direct impact on the quantity of PHB produced. Pyrosequencing of 16S rRNA transcripts showed changes in the active bacteria of the WAS microbial community as well as the acclimation of populations depending on sludge origin. The monitoring of the process appeared as the key factor for optimal PHB production by WAS. Different strategies are discussed and compared in terms of carbon yield and PHB content with the feast and famine selection process.
authors.affiliation: Université de Toulouse, INSA, UPS, LISBP, 135 Avenue de Rangueil, F-31077 Toulouse Cedex 4, France; INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés, F-31400 Toulouse, France; CNRS, UMR5504, F-31400 Toulouse, France; VEOLIA Environnement, Centre de Recherche sur l'Eau, Chemin de la Digue, BP 76, 78603 Maisons-Laffite cedex, France. Electronic address: laetitia.cavaille@insa-toulouse.fr.
authors.forename: Laëtitia
authors.initials: L
authors.lastname: Cavaillé
authors.forename: Estelle
authors.initials: E
authors.lastname: Grousseau
authors.forename: Mathieu
authors.initials: M
authors.lastname: Pocquet
authors.forename: Anne-Sophie
authors.initials: AS
authors.lastname: Lepeuple
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Uribelarrea
authors.forename: Guillermina
authors.initials: G
authors.lastname: Hernandez-Raquet
authors.forename: Etienne
authors.initials: E
authors.lastname: Paul
mesh_terms: D001419:Bacteria / Q000235:genetics / Q000378:metabolism; D061249:Batch Cell Culture Techniques / Q000379:methods*; D057919:Biological Oxygen Demand Analysis; D002087:Butyrates / Q000378:metabolism*; D005240:Feasibility Studies; D010758:Phosphorus / Q000378:metabolism*; D011091:Polyesters / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012722:Sewage / Q000737:chemistry*; D013997:Time Factors
chemical_list: D002087:Butyrates; D011091:Polyesters; D012336:RNA, Ribosomal, 16S; D012722:Sewage; D010758:Phosphorus
keywords: Direct accumulation; P limitation; Polyhydroxybutyrate (PHB); Waste activated sludge