What is a fed-batch system?
Fed-batch culture is, in the broadest sense, defined as an operational technique in biotechnological processes where one or more nutrients (substrates) are fed (supplied) to the bioreactor during cultivation and in which the product(s) remain in the bioreactor until the end of the run.
How growth is measured in a fed-batch system?
The growth rate can be controlled by the substrate concentration to avoid catabolite repression. The products are harvested only at the end of the run. The culture volume increases during the course of operation until the volume is full. Thereafter, a batch mode of operation is used to attain the final results.
What is design equation?
Equation which, based on production measurements or specifications, provides a performance property useful in design calculations. NOTE A design equation can be defined by applying reasonable extremes to the variables in a limit state equation to arrive at a conservative value of expected performance.
What is the difference between batch and fed-batch culture?
The main choices are: Batch, where no extra feeding is used from beginning to end of the process. Fed-batch, where feeding with substrate and supplements can extend the duration of culture for higher cell densities or switch metabolism to produce e.g. a recombinant protein.
How does fed-batch reactor work?
In fed-batch operations, intermittent or continuous feeding of nutrients is used to supplement the reactor contents and provide control over the substrate concentration. By starting with a relatively dilute solution of substrate and adding more nutrients as the conversion proceeds, high growth rates are avoided.
What are the examples of fed-batch fermentation?
Another application of fed-batch fermentation is in the accumulation of non-growth-associated products, for example antibiotic production, where a high concentration of cells is needed before the switchover of the metabolism of the cells for product formation in the stationary phase.
What is the characteristics of fed-batch culture?
Through the manipulation of the feed rates of the medium containing the substrate and nutrients, the fed-batch operation allows regulation of the concentration of key substances that control the cell growth and/or product formation rate.
Is a PFR the same as a PBR?
The most important characteristic of a PBR is that material flows through the reactor as a plug; they are also called plug flow reactors (PFR).
Is PFR a batch reactor?
PFR is the continuous type reactor and their is no axial mixing and it is segment of many batch reactor. MFR it is the reactor which has agitator feted and it also a continuous type. Batch reactor has input fed then the reaction occur and after o/p.
What is characteristic of fed-batch culture?
What is meant by fed-batch fermentation?
CFBF describes a modified semi-continuous cultivation approach, where varying volumes of the fermentation broth are replaced by fresh medium in such a way to partly recycle 20 to 40% of the fermentation broth.
Why is PFR more efficient than CSTR?
CSTR reduces concentration of reactant to minimum in less time than what PFR does. Rate of reaction is directly proportional to reactant concentration for positive order reactions. More the concentration more will be the rate. Hence PFR gives higher conversion than CSTR for positive order reactions.
Can fed-batch data be used to guide reactor sizing?
Under certain conditions fed-batch data can also be used to guide reactor sizing for other reactor configurations, provided that the rate of change in the reactor volume is substantially smaller than the initial reactor volume. However, Levenspiel plots are only valid for one reaction trajectory and are not an optimization tool.
What is the purpose of fed batch operations?
In fed-batch operations, intermittent or continuous feeding of nutrients is used to supplement the reactor contents and provide control over the substrate concentration. By starting with a relatively dilute solution of substrate and adding more nutrients as the conversion proceeds, high growth rates are avoided.
How is time profile calculated for fed-batch and continuous fermentations?
For fed-batch and continuous fermentations, nutrient feeding and broth harvest were carried out following a pre-set time profile of pump speed. This can be achieved in the “Time profile” setting under “Cascade” to a designated pump (Figure 5). For time duration calculation, EFT (elapsed fermentation time) was initiated at inoculation.
What is a fed-batch filtration system?
Fed-batch systems are commonly used in industry when the permeate is the desired product. Fed-batch filtration is an unsteady-state process: retained solutes accumulate in the system with time. Unsteady-state mass balance methods similar to those applied for batch operations can be used to derive equations for the retentate solute concentration.