Regulation of methanol oxidation and carbon dioxide fixation in Xanthobacter strain 25a grown in continuous culture
| Autor: | Wilhelmus Meijer, L.M. Croes, Lubbert Dijkhuizen |
|---|---|
| Přispěvatelé: | Groningen Biomolecular Sciences and Biotechnology |
| Jazyk: | angličtina |
| Rok vydání: | 1991 |
| Předmět: |
CALVIN CYCLE
H4-14 Biology Formate dehydrogenase Biochemistry Microbiology chemistry.chemical_compound DEHYDROGENASE CARBON DIOXIDE FIXATION Genetics Formate Xanthobacter CONTINUOUS CULTURE Molecular Biology AUTOTROPHY XANTHOBACTER Methanol dehydrogenase Methylamine Carbon fixation MIXTURES General Medicine HYDROGEN METHYLAMINE RUBISC/O GENE CLUSTERS chemistry PARACOCCUS-DENITRIFICANS BACTERIUM REGULATION METHANOL FORMATE Methanol DISSIMILATION Energy source METHYLOTROPHY HETEROTROPHIC METABOLISM Nuclear chemistry |
| Zdroj: | Archives of Microbiology, 155(2), 159-163. SPRINGER |
| ISSN: | 0302-8933 |
| Popis: | The regulation of C1-metabolism in Xanthobacter strain 25a was studied during growth of the organism on acetate, formate and methanol in chemostat cultures. No activity of methanol dehydrogenase (MDH), formate dehydrogenase (FDS) or ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisC/O) could be detected in cells grown on acetate alone over a range of dilution rates tested. Addition of methanol or formate to the feed resulted in the immediate induction of MDH and FDH and complete utilization (D = 0.10 h-1) of acetate and the C1-substrates. The activities of these enzymes rapidly dropped at the higher growth rates, which suggests that their synthesis is further controlled via repression by "heterotrophic" substrates such as acetate. Synthesis of RuBisC/O already occurred at low methanol concentrations in the feed, resulting in additive growth yields on acetate/methanol mixtures. The energy generated in the oxidation of formate initially allowed an increased assimilation of acetate (and a decreased dissimilation), resulting in enhanced growth yields on the mixture. RuBisC/O activity could only be detected at the higher formate/acetate ratios in the feed. The data suggest that synthesis of RuBisC/O and CO2 fixation via the Calvin cycle in Xanthobacter strain 25a is controlled via a (de)repression mechanism, as is the case in other facultatively autotrophic bacteria. Autotrophic CO2 fixation only occurs under conditions with a diminished supply of "heterotrophic" carbon sources and a sufficiently high availability of suitable energy sources. The latter point is further supported by the clearly more pronounced derepressing effect exerted by methanol compared to formate. |
| Databáze: | OpenAIRE |
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