title: Effect of acetate to biomass ratio on simultaneous polyhydroxybutyrate generation and direct microbial growth in fast growing microbial culture.
abstract: The study investigated the effect of variations in the acetate to biomass ratio on substrate storage potential, and the kinetics of substrate utilization. A series of batch experiments were conducted with biomass taken from the fill and draw reactor operated at a sludge age of 2 d. One of the batch reactors duplicated the substrate loading in the main reactor. The others were started with different initial acetate to biomass ratios both in lower and higher ranges. Increasing available acetate did not totally divert excess substrate to storage; the microbial culture adjusted the kinetics of the metabolic reactions to a higher growth rate so that more substrate could be utilized for direct growth at high acetate levels. Conversely, storage rate was increased, utilizing a higher substrate fraction for polyhydroxybutyrate generation when acetate concentration was lowered. The physiological and molecular bases of storage at low substrate levels were discussed.
authors.affiliation: Faculty of Civil Engineering, Environmental Engineering Department, Istanbul Technical University, 34469 Maslak, Istanbul, Turkey.
authors.forename: Yester
authors.initials: Y
authors.lastname: Biros
authors.affiliation: Faculty of Civil Engineering, Environmental Engineering Department, Istanbul Technical University, 34469 Maslak, Istanbul, Turkey.
authors.forename: Emine Ubay
authors.initials: EU
authors.lastname: Çokgör
authors.affiliation: Faculty of Civil Engineering, Environmental Engineering Department, Istanbul Technical University, 34469 Maslak, Istanbul, Turkey.
authors.forename: Nevin
authors.initials: N
authors.lastname: Yağcı
authors.affiliation: Faculty of Civil Engineering, Environmental Engineering Department, Istanbul Technical University, 34469 Maslak, Istanbul, Turkey.
authors.forename: Ilke
authors.initials: I
authors.lastname: Pala-Ozkok
authors.affiliation: Faculty of Science and Letters, Molecular Biology and Genetics Department, Istanbul Technical University, 34469 Maslak, Istanbul, Turkey; Dr. Orhan Öcalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, 34469 Maslak, Istanbul, Turkey.
authors.forename: Zeynep Petek
authors.initials: ZP
authors.lastname: Çakar
authors.affiliation: Faculty of Civil Engineering, Environmental Engineering Department, Istanbul Technical University, 34469 Maslak, Istanbul, Turkey. Electronic address: sozens@itu.edu.tr.
authors.forename: Seval
authors.initials: S
authors.lastname: Sözen
authors.affiliation: Faculty of Civil Engineering, Environmental Engineering Department, Istanbul Technical University, 34469 Maslak, Istanbul, Turkey; The Science Academy, 34353 Beşiktaş, Istanbul, Turkey.
authors.forename: Derin
authors.initials: D
authors.lastname: Orhon
mesh_terms: D000085:Acetates / Q000378:metabolism*; D018533:Biomass; D019149:Bioreactors; D053898:Biosynthetic Pathways / Q000502:physiology*; D006885:Hydroxybutyrates / Q000737:chemistry*; D007700:Kinetics; D011108:Polymers / Q000737:chemistry*; D012722:Sewage / Q000382:microbiology*; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D000085:Acetates; D006885:Hydroxybutyrates; D011108:Polymers; D012722:Sewage
keywords: Acetate; Modeling; Oxygen uptake rate; Polyhydroxybutyrate (PHB); Substrate storage