title: New Insight into the Role of the Calvin Cycle: Reutilization of CO2 Emitted through Sugar Degradation.
abstract: Ralstonia eutropha is a facultative chemolithoautotrophic bacterium that uses the Calvin-Benson-Bassham (CBB) cycle for CO2 fixation. This study showed that R. eutropha strain H16G incorporated (13)CO2, emitted by the oxidative decarboxylation of [1-(13)C1]-glucose, into key metabolites of the CBB cycle and finally into poly(3-hydroxybutyrate) [P(3HB)] with up to 5.6% (13)C abundance. The carbon yield of P(3HB) produced from glucose by the strain H16G was 1.2 times higher than that by the CBB cycle-inactivated mutants, in agreement with the possible fixation of CO2 estimated from the balance of energy and reducing equivalents through sugar degradation integrated with the CBB cycle. The results proved that the 'gratuitously' functional CBB cycle in R. eutropha under aerobic heterotrophic conditions participated in the reutilization of CO2 emitted during sugar degradation, leading to an advantage expressed as increased carbon yield of the storage compound. This is a new insight into the role of the CBB cycle, and may be applicable for more efficient utilization of biomass resources.
authors.affiliation: Department of Bioengineering, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan.
authors.forename: Rie
authors.initials: R
authors.lastname: Shimizu
authors.affiliation: Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Yudai
authors.initials: Y
authors.lastname: Dempo
authors.affiliation: Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Yasumune
authors.initials: Y
authors.lastname: Nakayama
authors.affiliation: Department of Bioengineering, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nakamura
authors.affiliation: Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Bamba
authors.affiliation: Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Eiichiro
authors.initials: E
authors.lastname: Fukusaki
authors.affiliation: Department of Bioengineering, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Fukui
mesh_terms: D050260:Carbohydrate Metabolism / Q000187:drug effects; D002244:Carbon / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism*; D002247:Carbon Isotopes; D020118:Cupriavidus necator / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D005947:Glucose / Q000494:pharmacology; D006885:Hydroxybutyrates / Q000378:metabolism; D055442:Metabolome / Q000187:drug effects; D055432:Metabolomics; D010788:Photosynthesis / Q000187:drug effects; D011091:Polyesters / Q000378:metabolism; D000094122:Polyhydroxybutyrates
chemical_list: D002244:Carbon; D002245:Carbon Dioxide; D002247:Carbon Isotopes; D005947:Glucose; D006885:Hydroxybutyrates; D011091:Polyesters; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates