title: Rapid selection of glucose-utilizing variants of the polyhydroxyalkanoate producer Ralstonia eutropha H16 by incubation with high substrate levels.
abstract: OBJECTIVE
  The application of Ralstonia eutropha H16 for producing polyhydroxyalkanoates as bioplastics is limited by the incapability of the bacterium to utilize glucose as a growth substrate. This study aims in characterizing glucose-utilizing strains that arose after incubation with high glucose levels, in comparison with previously published mutants, generated either by mutagenesis or by metabolic engineering.
  
  
  RESULTS
  Cultivations on solid and liquid media showed that the application of high substrate concentrations rapidly induced a glucose-positive phenotype. The time span until the onset of growth and the frequency of glucose-utilizing colonies were correlated to the initial glucose concentration. All mutants exhibited elevated activities of glucose-6-phosphate dehydrogenase. The glucose-positive phenotype was abolished after deleting genes for the N-acetylglucosamine phosphotransferase system.
  
  
  CONCLUSIONS
  A procedure is provided for selecting glucose-utilizing R. eutropha H16 in an unprecedented short time period and without any mutagenic treatment. An altered N-acetylglucosamine phosphotransferase system appears to be a common motif in all glucose-utilizing mutants examined so far.
  
  
  CONCLUSIONS
  The correlation of the applied glucose concentration and the appearance of glucose-utilizing mutants poses questions about the randomness or the specificity of adaptive mutations in general. Furthermore, glucose-adapted strains of R. eutropha H16 could be useful for the production of bioplastics.
authors: Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany.
authors: A
authors: A
authors: Franz
authors: R
authors: R
authors: Rehner
authors: A
authors: A
authors: Kienle
authors: H
authors: H
authors: Grammel
mesh_terms: D000117:Acetylglucosamine / Q000378:metabolism; D019149:Bioreactors; D020118:Cupriavidus necator / Q000145:classification / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D007218:Industrial Microbiology; D060847:Metabolic Engineering; D010770:Phosphotransferases / Q000378:metabolism; D010969:Plastics / Q000378:metabolism; D054813:Polyhydroxyalkanoates / Q000096:biosynthesis*
chemical_list: D010969:Plastics; D054813:Polyhydroxyalkanoates; D005954:Glucosephosphate Dehydrogenase; D010770:Phosphotransferases; D005947:Glucose; D000117:Acetylglucosamine