Generalizations in Multisubstrate Kinetics

Generally, in multicomponent media, substrates will be utilized sequentially. Physiologically, two different responses can be distinguished, known as cata-bolite repression and inhibition, both resulting in a diauxic growth pattern. Remarkable differences in growth behavior can be observed comparing batch and continuous operation in a CSTR (Harder and Dijkhuizen, 1975), due to the existence of much lower steady-state concentrations of Sj in CSTRs so that the effects of both repression and inhibition may be absent or reduced. 

Yoon et al. (1977), Aris and Humphrey (1977), and Knorre (1976) derived generalized Monod equations for multisubstrate systems, based on the following sequence of reactions  

Another generalization of the Monod-type kinetics was suggested by Tsao and Hanson (1975) and by Tsao and Yang (1976). They assumed the existence of growth-enhancing substrates Si and of essential substrates resulting in an equation 

The effect of growth-enhancing substrates is given as the sum of Monod-type 

With an aerobic bioprocess it is evident that, in addition to substrate, O2 can be rate limiting. The curve for biomass concentration increasing with time in a batch run is significantly influenced by the oxygen transfer rate quantified by the volumetric transfer coefficient This situation of an external 

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