Fermentation Kinetics Dialog

This dialog appears when you click on the reaction kinetics button from the reaction tab of the following operations:

Variable Definitions, Ranges and Default Values

The following table shows a brief description of the variables appearing in this dialog. The table also displays their default values and their generally acceptable range:

Variable	Default Value	Range

○ Rate Reference Component The component that the rate is calculated for.	(none)	Compo-nent
○ Initial Guess of Extent (%) An initial guess of the reaction extent based on the limiting component, which is used only when a first-order biomass term is selected and there is no biomass in the feed.	100.0	0-100
○ μmax (1/h) The maximum specific biomass growth rate.	0.5	Any Number
○ α Constant	1.0	Any Number
○ β (1/h) Constant	0.0	Any Number
Biomass-Term:
○ Biomass The biomass component.	(none)	Compo-nent
○ Biomass Term Order The kinetic expression of the biomass term in the rate equation.	First Order [B]	First Order / None
Substrate Terms (S1, S2, S2):
○ Substrate The substrate component	(none)	Compo-nent
○ Substrate Expression The Expressions of the substrate terms.	Monod	Monod/ Haldane/ Inhibition/ First Order / None
○ Monod constant Ks (mg/L)	35.0	Any Number
○ Haldane inhibition constant Ki (mg/L)	1.0	Non Zero
○ Inhibition constant Kmic (mg/L)	100000.	Non Zero

Symbol Key: ○ User-specified value (always input); ● Calculated value (always output); ◙ Sometimes input, sometimes output

Specification Choices / Comments

The following describes the available specification choices in this dialog; for more details on how these are implemented, please view see Batch Kinetic Fermentation: Modeling Calculations or Continuous Kinetic Fermentation: Modeling Calculations.

S1, S2, S3 terms

Each of the three substrate terms can take the form of the following expressions: Monod, Haldane, Inhibition, first order or none. They can represent the kinetic expression for three different components (substrates or reaction products). More specifically the S3 term can be used as the kinetic expression of the inhibitor component.

B-Term

This is for identifying the Biomass component (if any) that affects the kinetics of this reaction. Please note that the ‘Biomass’ drop-down menu displays all components that have been identified by the user as biomass components. More specifically, ‘Is Biomass?’ is a component property specified on the IDs tab of the Pure Component Properties Dialog of a component (through Tasks \ Pure Components \ Register, Edit/View Properties). The availability of multiple Biomass components offers the user the flexibility to track different types of biomass (e.g., heterotrophic biomass, nitrifiers or autotrophic biomass) and use the appropriate type of biomass to catalyze each reaction.

If a first-order biomass term is selected, and the concentration of the selected biomass component in the feed stream is zero (i.e. the reaction is autocatalytic), then you must also specify an initial guess for the reaction extent % with respect to the selected rate reference component.

Finally add Start / End Criteria for a fermentation press on corresponding button and a new dialog Reaction Kinetics: Start / End Criteria Dialog appears enabling you to set these options. Start & End criteria can only be set for batch fermentation kinetic operations.