[Kinetics of the growth of colonies of Mucor plumbeus and Mortierella ramanniana fungi on agarized media with glucose].

The growth kinetics of Mucor plumbeus and Mortierella ramanniana colonies was studied during cultivation of these two soil fungi on solid media with glucose as a limiting substrate. Within the whole studied range of glucose concentrations (s), the radial growth rate of colonies (Kr) can be satisfactorily described with the following equation that takes substrate inhibition into consideration: (Formula: see text) The values of kinetic parameters for M. plumbeus and Mort. ramanniana, respectively, are: the maximal radial growth rate Kr(max), 0.434 and 0.075 mm/hr; the saturation constant Ks, 6.5 and 5.6 mg/l; the substrate inhibition constant, Ks(i), 3315 and 98.6 mg/l. The mechanism of substrate inhibition is manifested in a decrease in the width (volume) of the peripheral zone of the colonial growth at high substrate concentrations, and is not related to a decrease in the specific growth rate of the fungi. Regardless of the drastic differences in the Kr of the two cultures, their specific growth rates are similar and depend on the substrate concentration according to in the same pattern.