title: Continuous production of poly-3-hydroxybutyrate by Ralstonia eutropha in a two-stage culture system.
abstract: Poly-3-hydroxybutyrate (PHB) is mainly accumulated by Ralstonia eutropha under unbalanced growth conditions, which limits its production in batch or fed-batch modes. The continuous production of PHB was investigated in a two-stage continuous culture system. The first-stage produced cell mass giving the maximal cell dry weight of 27.1 g l(-1) at 0.21 h(-1) of dilution rate. High specific cell growth rate results in the decrease of PHB synthesis under glucose-limited and nitrogen-rich conditions in the first-stage. The second-stage produced PHB giving the maximal PHB concentration of 47.6 g l(-1) at 0.14 h(-1) of dilution rate. Specific PHB synthetic rate reached highest value at low dilution rate under nitrogen-limited condition in the second-stage, and decreased with the increase of ammonium concentration in the culture. In the continuous culture system, the maximal PHB productivity could reach 1.43 g l(-1) h(-1) at a dilution rate of 0.12 h(-1), but with relatively low PHB content of 47.6%. Maximal yield of PHB on glucose could reach 0.36 g g(-1) glucose at 0.075 h(-1) of dilution rate with relatively high PHB productivity of 1.23 g l(-1) h(-1) and PHB content of 72.1%, respectively.
authors.affiliation: School of Biotechnology, Wuxi University of Light Industry, Jiangsu Province, Wuxi, People's Republic of China.
authors.forename: G
authors.initials: G
authors.lastname: Du
authors.forename: J
authors.initials: J
authors.lastname: Chen
authors.forename: J
authors.initials: J
authors.lastname: Yu
authors.forename: S
authors.initials: S
authors.lastname: Lun
mesh_terms: D020118:Cupriavidus necator / Q000737:chemistry / Q000254:growth & development / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D006885:Hydroxybutyrates / Q000378:metabolism*; D007218:Industrial Microbiology / Q000379:methods*; D011091:Polyesters / Q000378:metabolism*; D000644:Quaternary Ammonium Compounds / Q000378:metabolism; D000094122:Polyhydroxybutyrates
chemical_list: D005947:Glucose; D006885:Hydroxybutyrates; D011091:Polyesters; D000644:Quaternary Ammonium Compounds; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates