FORMAL KINETICS OF POLY-BETA-HYDROXYBUTYRIC ACID (PHB) PRODUCTION IN ALCALIGENES-EUTROPHUS-H16 AND MYCOPLANA-RUBRA-R14 WITH RESPECT TO THE DISSOLVED-OXYGEN TENSION IN AMMONIUM-LIMITED BATCH CULTURES

Under chemolithoautotrophic growth conditions with the organism Alcaligenes eutrophus H16 the exponential growth phase is characterized by two different growth rates, each associated with different specific rates of ammonium consumption. On the basis of the analytical determination of Poly-β-hydroxybutyric acid (PHB), it can be conclusively shown that PHB is synthesized even during the exponential growth phase at a specific rate proportional to the specific growth rates of total biomass. After complete consumption of ammonium, the increase of biomass is exclusively due to PHB synthesis, whereas protein and rest biomass (cell dry weight minus PHB) remain constant. After an extended period of fermentation, the PHB content reaches a saturation value. The transient phase between the growth and the storage phase is very short in comparison to the duration of the whole fermentation. In the case of Alcaligenes eutrophus, strain H 16, high concentrations of dissolved oxygen strongly influence growth as well as PHB synthesis. © 1979 Springer-Verlag.