Bioreactors Flashcards
Bioreactor
A device or system meant to grow animal
cells or tissues in the context of cell culture. These devices are being
developed for use in tissue engineering or biochemical engineering.
Fermenters
The cultivation of microbes,
proteins, industrial product (acetic acid, alcohol etc.) under monitored controlled
environmental and operational conditions up to an industrial scale.
What are some of the properties of animal cells that sets constrains designing animal cell bioreactor.
1) Cell size (10-20um) is small.
2) More fragile
3) They grow slowly than most bacteria and fungi
4) Toxic metabolites such as ammonium & lactate can be produced during growth.
What is done to ensure adequate mixing occurs in bioreactors.
At low stirring speeds, bioreactor should be designed with a round bottom. Impeller blades which are fitted at the end of mechanical drive shafts. Vessel should be made of glass or stainless steel.
Classification of Bioreactor in terms of process requirements
1.) Aerobic bioreactor
2) Anaerobic bioreactor
3) Immobilized cell bioreactors
Classification of Bioreactor on the basis of mode of operation
1) Batch
2) Fed Batch
3) Continuous
Give one example of batch mode bioreactor
Stirred tank Bioreactor
Give one example of fed-batch bioreactor
Fluidized bed bioreactor
Give one example of continuous bioreactor
Chemostat
Differences between fed-batch and batch
1) Fed- batch
2) Batch
1- Continuous medium addition, 2- Continuous addition and removal of medium can not be done
1- Addition of selected components, 2- Addition of complete medium once
1- Dilution of the by-products, 2- removal/dilution of byproducts can not be done.
1- Changing environment for cells, 2- Constant environment.
1- Lower stability of product of interest.
2- Higher stability of product
1- Alkali addition
2- Less alkali addition for pH control
Components/ Parameters of a bioreactor
1- Agitation
2- Aeration
3- Baffles
4- Sparger
5- Foam control
6- Temperature
7- pH
8- Viscosity
9- Sterilization
10- Scale up
Types of bioreactor
1) Stirred types of bioreactor
2) Air lift bioreactor
3) Fluidized bed bioreactor
4) Tower bioreactor
5) Continuous bioreactor
6) Gaseous phase bioreactor
Chemostate
Chemical environment is constant.
Cell grow at max density
when some nutrient like vitamin, is growth limiting.
Turbidostate
Cells grow to achieve higher density.
Downstream processing of bioreactor
1) Filtration: Surface filtration, depth filtration, cross flow filtration ,membrane filtration
etc.
2) Centrifugation: Difficulty arise due to
small differences in the density of particle and medium .
3) Ion exchange resins: Dextrone ,cellulose,
polyamines.
4) Chromatography: Affinity chromatography
