Special Components

Certain components in the set of registered components in a process file have a special meaning for the application’s simulation engine. These components are selected from the Pure Component Registration Dialog. Currently, there are two such components:

1.   The ‘Primary Biomass’ component:
The component assumed to represent the main (primary) biomass in the current process (recipe). Portions of other components that are considered intracellular (or sorbed) will be assumed to be incorporated into the mass (amount) of this compound and follow the fate of this component when separated from the main process stream (e.g. through a filter). If the component designated as ‘Primary Biomass’ is formed (as a reaction product), you can specify distinct intra-cellular percentages for other products of the reaction to indicate that they are sorbed (or part of) the primary biomass produced. Similarly, if water produced or present becomes assimilated with the biomass cells, the bio-reaction’s interface will allow you to choose a ‘Water’ component and a primary biomass water content and the simulation engine will automatically assign as much ‘Water’ needed as intracellular. If the ‘Primary Biomass’ component has been assigned a removal coefficient, the system will use the same removal coefficient for components that have an intracellular portion. The ‘Primary Biomass’ component is selected only amongst component whose ‘IsBiomass’ flag has been set (see Pure Component: IDs). The percentage of a component that is considered intracellular (incorporated in the Primary Biomass component) can be specified in the Input Stream Dialog: Composition, etc. Tab or the Bio-Reaction Stoichiometry Balance Dialog. Note that in those dialogs, the extracellular % is set (complementary value to intracellular %).

2.   The ‘Activity-Reference’ component:
If a component has been designated as the ‘Activity-Reference’ component then its concentration, along with the potency index or basis (also defined on the Pure Component Registration Dialog), is used to determine the activity strength of a stream. The potency index of a component represents how many (arbitrary) units of activity (U) should be accounted for each mg of the active component present in a stream. The activity value of a stream is displayed on the first tab of a stream’s i/o simulation dialog.