Fecha de publicación: 2006.
We assessed the effects of different arcA mutations on poly(3- hydroxybutyrate) (PHB) synthesis in recombinant Escherichia coli strains carrying the pha synthesis genes from Azotobacter sp. strain FA8. The arcA mutations used were an internal deletion and the arcA2 allele, a leaky mutation for some of the characteristics of the Arc phenotype which confers high respiratory capacity. PHB synthesis was not detected in the wild-type strain in shaken flask cultures under low-oxygen conditions, while ArcA mutants gave rise to polymer accumulation of up to 24% of their cell dry weight. When grown under microaerobic conditions in a bioreactor, the arcA deletion mutant reached a PHB content of 27% ± 2%. Under the same conditions, higher biomass and PHB concentrations were observed for the strain bearing the arcA2 allele, resulting in a PHB content of 35% ± 3%. This strain grew in a simple medium at a specific growth rate of 0.69 ± 0.07 h-1, whereas the deletion mutant needed several nutritional additives and snowed a specific growth rate of 0.56 ± 0.06 h-1. The results presented here suggest that arcA mutations could play a role in heterologous PHB synthesis in microaerobiosis. Copyright © 2006, American Society for Microbiology. All Rights Reserved.
Afiliación de los autores: Pettinari, M.J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Afiliación de los autores: Galvagno, M.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Afiliación de los autores: Méndez, B.S. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Palabras claves: Biomass; Cell culture; Escherichia coli; Mutagenesis; Strain; Synthesis (chemical); ArcA mutants; Leaky mutation; Microaerobiosis; Poly(3-hydroxybutyrate) synthesis; Organic polymers; poly(3 hydroxybutyric acid); bacteriology; gene; mutagenicity; recombination; aerobic metabolism; allele; arcA gene; arcA2 gene; article; Azotobacter; Azotobacter FA8; bacterial gene; bacterial growth; bacterial strain; biomass; bioreactor; dry weight; Escherichia coli; gene deletion; gene mutation; nonhuman; pha gene; phenotype; synthesis; wild type; Aerobiosis; Bacterial Outer Membrane Proteins; Biomass; Culture Media; Escherichia coli; Escherichia coli Proteins; Gene Expression Regulation, Bacterial; Hydroxybutyrates; Mutation; Polyesters; Recombination, Genetic; Repressor Proteins; Arca; Azotobacter; Bacteria (microorganisms); Escherichia coli.
Repositorio: Biblioteca Digital (UBA-FCEN). Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales