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  • 1
    Electronic Resource
    Electronic Resource
    Growth yields and the efficiency of oxidative phosphorylation of Paracoccus denitrificans during two- (carbon) substrate-limited growth (1979)
    Springer
    Archives of microbiology 121 (1979), S. 213-223 
    Details
    ISSN: 1432-072X
    Keywords: Oxidative phosphorylation ; Chemostat culture ; Growth yield ; Mixed substrates ; Ribulose-bisphosphate cycle ; Cytochrome c ; Single cell protein ; Methanol ; Paracoccus denitrificans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Paracoccus denitrificans was grown aerobically during two-(carbon)substrate-limitation on mannitol and methanol in chemostat cultures. Theoretical growth parameters were calculated based on the presence of 2 or 3 sites in the electron-transport chain of Paracoccus denitrificans. Experimental growth parameters determined during two-(carbon)substrate growth were conform to the presence of 3 sites of oxidative phosphorylation, while cells grown only on mannitol possessed 2 sites. The maximum growth yield on adenosine triphosphate (ATP), corrected for maintenance requirements, determined in chemostat experiments in which the methanol concentration is less than 2.11 times the mannitol concentration was 8.6 g of biomass. When the methanol concentration was more than 2.11 times the mannitol concentration the maximum growth yield on adenosine triphosphate decreased due to the more energy consuming process of CO2-assimilation. Cells use methanol only as energy source to increase the amount of mannitol used for assimilation purposes. When the methanol concentration in chemostat experiments was more than 2.11 times the mannitol concentration, all mannitol was used for assimilation and excess energy derived from methanol was used for CO2-assimilation via the ribulose-bisphosphate cycle. The synthesis of ribulosebisphosphate carboxylase was repressed when the methanol concentration in chemostat experiments was less than 2.11 times the mannitol concentration or when Paracoccus denitrificans was grown in batch culture on both methanol and mannitol. When in chemostat experiments the methanol concentration was more than 2.11 times the mannitol concentration ribulose-bisphosphate carboxylase activity could be demonstrated and CO2-assimilation will occur. It is proposed that energy produced in excess activates or derepresses the synthesis of the necessary enzymes of the ribulose-bisphosphate cycle in Paracoccus denitrificans. Consequently growth on any substrate will be carbonas well as energy-limited. When methanol is present in the nutrient cells of Paracoccus denitrificans synthesize a CO-binding type of cytochrome c, which is essential for methanol oxidase activity. The reason for the increase in efficiency of oxidative phosphorylation from 2 to 3 sites is most probably the occurrence of this CO-binding type of cytochrome c in which presence electrons preferentially pass through the a-type cytochrome region of the electron-transport chain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00425058
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  • 2
    Electronic Resource
    Electronic Resource
    Energetic aspects of growth of Paracoccus denitrificans: oxygen-limitation and shift from anaerobic nitrate-limination to aerobic succinate-limitation (1983)
    Springer
    Archives of microbiology 135 (1983), S. 229-236 
    Details
    ISSN: 1432-072X
    Keywords: Cytochrome oxidase ; Paracoccus denitrificans ; Growth yields ; Oxidative phosphorylation ; CO-Ligands ; Chemostat ; Proton translocation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 1. Growth yields and efficiency of energy conservation were the same for aerobic succinate-limited and oxygen-limited cells of Paracoccus denitrificans. 2. A shift from anaerobic nitrate-limitation to aerobic succinatelimitation showed that before and after the shift cells grew with the same capacity of energy conservation. 3. Respiration-driven proton translocation showed the presence of H+-translocating sites 1 and 2, which translocate respectively 2–3 and 4 protons per 2 electrons in oxygen-, anaerobic nitrate-and aerobic succinate-limited cells. 4. Cytochrome spectra and flash-photolysis spectra of oxygen- and nitrate-limited cells gave evidence for the presence of an alternative oxidase, cytochrome a 1, never before recognized in Paracoccus denitrificans. 5. Only a-type cytochromes liganded with CO could be flash-photolysed. No evidence for a functional cytochrome o was found in photolysis experiments. 6. Fast oxidation, before photolysis, of the bc-pool after introduction of oxygen in a CO-liganded sample at-20° to-30° C, indicated the presence of a cytochrome oxidase other than cytochrome a 1 with a very high affinity for oxygen and a low affinity for CO. 7. In photochemical action spectra, light released CO-inhibition of respiration, but the release was independent of the wavelength used (560–610 nm).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00414485
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    Paper (German National Licenses)
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