Monod population growth kinetics

Microbial Biotransformation. Microbial population growth and substrate utilization can be described via Monod s (35) analogy with Michaelis-Menten enzyme kinetics (36). The growth of a microbial population in an unlimiting environment is described by dN/dt = u N, where u is called the "specific growth rate and N is microbial biomass or population size. The Monod equation modifies this by recognizing that consumption of resources in a finite environment must at some point curtail the rate of increase (dN/dt) of the population ... 

For limiting nutrients, cellular concentrations are constant under conditions of steady-state growth. To ensure that the limiting nutrient is not diluted in the microbial population, kmt must be greater than the maximal growth rate, /imax. This limiting condition sets a minimum for the value of the Monod constant, Kmd = / max /[7]- Note that while Monod kinetics are more applicable than first-order kinetics for many ecological uptake processes, solutions of the above equations require considerably more a priori information [48]. 

Monod kinetics are often a better description of the reactions occurring in sediment. Assume that the flux conditions are similar to problem 2 for SOD. The maximum bacterial growth rate is 0.5 hr in these sediments, and the halfsaturation coefficient is 1 g/m of oxygen. What is the microbacterial population for the 0.5- and 5-g/m -day cases (Hint, use a change of variables to solve for / = dCIdz.) Plot oxygen concentration for each case on the same scale as for problem 2 and compare the two plots. 

Figure 5.52. Conceptual representations of the interactive model, (a) is converted to Pi by an enzyme that requires S2 as a cofactor, (b) Substrates and S2 from two parallel pathways are combined by enzyme to produce a product P that is required for growth, (c) Plots of lines of constant dimensionless specific growth rate p/Prmx as a function of two dimensionless substrate concentrations for interactive models of the Megee type (cf. Equ. 5.169) with Monod kinetics (Reprinted with permission from In Microbial Population Dynamics, Bader, 1982. Copyright CRC Press, Inc., Boca Raton, FL.)...

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