title: Production of poly-(beta-hydroxybutyric-co-beta-hydroxyvaleric) acids.
abstract: Alcaligenes latus, Alcaligenes eutrophus, Bacillus cereus, Pseudomonas pseudoflava, Pseudomonas cepacia, and Micrococcus halodenitrificans were found to accumulate poly-(beta-hydroxybutyric-co-beta-hydroxyvaleric) acid [P(HB-co-HV)] copolymer when supplied with glucose (or sucrose in the case of A. latus) and propionic acid under nitrogen-limited conditions. A fed-batch culture of A. eutrophus produced 24 g of poly-beta-hydroxybutyric acid (PHB) liter-1 under ammonium limitation conditions. When the glucose feed was replaced with glucose and propionic acid during the polymer accumulation phase, 17 g of P(HB-co-HV) liter-1 was produced. The P(HB-co-HV) contained 5.0 mol% beta-hydroxyvaleric acid (HV). Varying the carbon-to-nitrogen ratio at a dilution rate of 0.15 h-1 in a chemostat culture of A. eutrophus resulted in a maximum value of 33% (wt/wt) PHB in the biomass. In comparison, A. latus accumulated about 40% (wt/wt) PHB in chemostat culture under nitrogen-limited conditions at the same dilution rate. When propionic acid was added to the first stage of a two-stage chemostat, A. latus produced 43% (wt/wt) P(HB-co-HV) containing 18.5 mol% HV. In the second stage, the P(HB-co-HV) increased to 58% (wt/wt) with an HV content of 11 mol% without further addition of carbon substrate. The HV composition in P(HB-co-HV) was controlled by regulating the concentration of propionic acid in the feed. Poly-beta-hydroxyalkanoates containing a higher percentage of HV were produced when pentanoic acid replaced propionic acid.
authors.affiliation: Department of Chemical Engineering, Ecole Polytechnique de Montréal, Quebec, Canada.
authors.forename: B A
authors.initials: BA
authors.lastname: Ramsay
authors.forename: K
authors.initials: K
authors.lastname: Lomaliza
authors.forename: C
authors.initials: C
authors.lastname: Chavarie
authors.forename: B
authors.initials: B
authors.lastname: Dubé
authors.forename: P
authors.initials: P
authors.lastname: Bataille
authors.forename: J A
authors.initials: JA
authors.lastname: Ramsay
mesh_terms: D000421:Alcaligenes / Q000378:metabolism; D001409:Bacillus cereus / Q000378:metabolism; D001419:Bacteria / Q000378:metabolism*; D008837:Micrococcus / Q000378:metabolism; D010421:Pentanoic Acids / Q000378:metabolism; D011091:Polyesters / Q000378:metabolism*; D011422:Propionates / Q000378:metabolism; D011549:Pseudomonas / Q000378:metabolism; D000094122:Polyhydroxybutyrates
chemical_list: D010421:Pentanoic Acids; D011091:Polyesters; D011422:Propionates; C052620:poly(3-hydroxybutyrate)-co-(3-hydroxyvalerate); D000094122:Polyhydroxybutyrates; C029658:propionic acid