title: Kinetic analysis on formation of poly(3-hydroxybutyrate) from acetic acid by Ralstonia eutropha under chemically defined conditions.
abstract: Batch cultures of Ralstonia eutropha in chemically defined media with acetic acid (HAc) as the sole carbon source were conducted to investigate acetate utilization, formation of poly(3-hydroxybutyrate) (PHB) and growth of active biomass (ABM) under different carbon to nitrogen (C/N) weight ratios. The specific acetate utilization rate based on ABM approached 0.16 g/g ABM h(-1), which was not affected very much by the extracellular HAc concentration from 1 to 5 g/l, but was affected by the C/N weight ratio. A low C/N ratio or high nitrogen supply sped up the specific acetate utilization rate to produce more ABM and less PHB. A high HAc concentration (>6 g/l), however, depressed acetate utilization as well as the ABM growth and PHB formation. A high cell mass concentration enhanced the tolerance of R. eutropha to the toxicity of HAc at pH 7 to 8.5. The viscosity-average molecular size of PHB generally increased first and then declined in batch cultures. Larger PHB molecules and less PHB per ABM were produced at a low C/N ratio with enough nutrient nitrogen than those under a high C/N ratio with less nutrient nitrogen available.
authors: Department of Chemical Engineering, Hong Kong University of Science and Technology, Clear Bay, Kowloon, China.
authors: J
authors: J
authors: Wang
authors: J
authors: J
authors: Yu
mesh_terms: D019342:Acetic Acid / Q000378:metabolism*; D018533:Biomass; D002244:Carbon / Q000378:metabolism; D003470:Culture Media / Q000737:chemistry; D020118:Cupriavidus necator / Q000254:growth & development* / Q000378:metabolism*; D006885:Hydroxybutyrates / Q000378:metabolism*; D007700:Kinetics; D009584:Nitrogen / Q000378:metabolism; D011091:Polyesters / Q000378:metabolism*; D000094122:Polyhydroxybutyrates
chemical_list: D019342:Acetic Acid; D002244:Carbon; D003470:Culture Media; D006885:Hydroxybutyrates; D009584:Nitrogen; D011091:Polyesters; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates