title: Photosynthetic mixed culture polyhydroxyalkanoate (PHA) production from individual and mixed volatile fatty acids (VFAs): substrate preferences and co-substrate uptake.
abstract: This work studied the effect of the substrate feeding composition on the polyhydroxyalkanoate (PHA) accumulation capacity of an acetate enriched photosynthetic mixed culture (PMC). From the six tested organic acids - malate, citrate, lactate, acetate, propionate and butyrate - only the three volatile fatty acids (VFAs) enabled PHA production, with acetate and butyrate leading to polyhydroxybutyrate (PHB) formation and propionate leading to a HB:HV copolymer with a 51% fraction of hydroxyvalerate (HV). Also, results showed an acceleration of butyrate and propionate consumption when fed in the presence of acetate, suggesting that the latter can act as a co-substrate for butyrate and propionate uptake. Furthermore, results suggest that some PMC bacterial groups present a substrate preference for butyrate in relation to acetate and propionate. These findings indicate the possibility of feeding the PMC with cheap VFA rich fermented wastes, leading to a more cost-effective and environmentally sustainable PHA production system.
authors.affiliation: REQUIMTE/CQFB, Chemistry Dpt., FCT, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: J C
authors.initials: JC
authors.lastname: Fradinho
authors.affiliation: REQUIMTE/CQFB, Chemistry Dpt., FCT, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: A
authors.initials: A
authors.lastname: Oehmen
authors.affiliation: REQUIMTE/CQFB, Chemistry Dpt., FCT, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal. Electronic address: amr@fct.unl.pt.
authors.forename: M A M
authors.initials: MA
authors.lastname: Reis
mesh_terms: D000085:Acetates / Q000378:metabolism; D053898:Biosynthetic Pathways / Q000502:physiology*; D001709:Biotechnology / Q000379:methods*; D002087:Butyrates / Q000378:metabolism; D002849:Chromatography, Gas; D002851:Chromatography, High Pressure Liquid; D005232:Fatty Acids, Volatile / Q000378:metabolism*; D006885:Hydroxybutyrates / Q000378:metabolism; D017404:In Situ Hybridization, Fluorescence; D008856:Microscopy, Fluorescence; D015345:Oligonucleotide Probes / Q000235:genetics; D010788:Photosynthesis / Q000502:physiology*; D011091:Polyesters / Q000378:metabolism; D054813:Polyhydroxyalkanoates / Q000096:biosynthesis*; D011422:Propionates / Q000378:metabolism; D013379:Substrate Specificity; D000094122:Polyhydroxybutyrates
chemical_list: D000085:Acetates; D002087:Butyrates; D005232:Fatty Acids, Volatile; D006885:Hydroxybutyrates; D015345:Oligonucleotide Probes; D011091:Polyesters; D054813:Polyhydroxyalkanoates; D011422:Propionates; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates
keywords: Co-substrate uptake; Photosynthetic mixed cultures; Polyhydroxyalkanoates (PHA); Substrate preferences; Volatile fatty acids (VFAs)