title: Volatile fatty acids influence on the structure of microbial communities producing PHAs.
abstract: Polyhydroxyalkanoates (PHAs) can be produced by microorganisms and are a biodegradable alternative to fossil-fuel based plastics. Currently, the focus is on reducing production costs by exploring alternative substrates for PHAs production, and on producing copolymers which are less brittle than monomers. Accordingly, this study used a substrate consisting of wastewater from waste-glycerol fermentation, supplemented with different amounts of acetic and propionic acids. These substrates were used to feed mixed microbial communities enriched from activated sludge in a sequencing batch reactor. A reactor supplemented with 2 mL of acetic acid produced 227.8 mg/L of a homopolymer of hydroxybutyrate (3 HB); 4 mL of acetic acid produced 279.8 mg/L 3 HB; whereas 4 mL of propionic acid produced 673.0 mg/L of a copolymer of 3 HB and 3 HV (hydroxyvalerate). Ribosomal Intergenic Spacer Analysis (RISA) was used to show the differences between the communities created in the reactors. Thauera species predominated in biomass that produced 3 HB; Paracoccus denitrificans in the biomass that produced 3 HB-co-3 HV. Because P. denitrificans produced the more desirable copolymer, it may be advantageous to promote its growth in PHAs-producing reactors by adding propionate.
authors.affiliation: Department of Environmental Biotechnology University of Warmia and Mazury in Olsztyn Olsztyn Poland Department of Environmental Biotechnology, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland.
authors.forename: Slawomir
authors.initials: S
authors.lastname: Ciesielski
authors.affiliation: Department of Environmental Biotechnology University of Warmia and Mazury in Olsztyn Olsztyn Poland Department of Environmental Biotechnology, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland.
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Przybylek
mesh_terms: D019342:Acetic Acid; D019149:Bioreactors / Q000382:microbiology*; D058448:Biota / Q000187:drug effects*; D003470:Culture Media / Q000737:chemistry; D005232:Fatty Acids, Volatile / Q000378:metabolism*; D005990:Glycerol / Q000378:metabolism; D007220:Industrial Waste; D054813:Polyhydroxyalkanoates / Q000378:metabolism*; D011422:Propionates; D012722:Sewage / Q000382:microbiology*
chemical_list: D003470:Culture Media; D005232:Fatty Acids, Volatile; D007220:Industrial Waste; D054813:Polyhydroxyalkanoates; D011422:Propionates; D012722:Sewage; C029658:propionic acid; D005990:Glycerol; D019342:Acetic Acid
keywords: RISA; Thauera sp; biopolymers; microbial community; polyhydroxyalkanoates