Journal article
Poly(3-hydroxybutyrate) synthesis by recombinant Escherichia coli arcA mutants in microaerobiosis
Departamento de Química Biológica. Facultad de Ciencias Exactas y Naturales, Ciudad Universitaria-Pabellón 2, 1428 Buenos Aires, Argentina.1
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 showed 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.
Language: | English |
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Publisher: | American Society for Microbiology |
Year: | 2006 |
Pages: | 2614-20 |
ISSN: | 10985336 and 00992240 |
Types: | Journal article |
DOI: | 10.1128/AEM.72.4.2614-2620.2006 |