2. Definition of bioreactors
Bioreactor may refer to any manufactured and engineered device or
system that support a biological active environment.
A bioreactor is a vessels which has provision of cell cultivation
under sterile condition and control of environmental condition e.g.,
ph , temperature , concentration of product and substrate and liquid
flow rate and some gasses like dissolved oxygen , nitrogen & carbon
dioxide etc.
This process can be either aerobic or anaerobic.
3. Bioreactor are commonly cylindrical in shape ,ranges in size
from liters to cubic meters and often made up of stainless
steel.
4.
5. A typical bioreactor consists of following parts:
Agitator-it is used for the mixing of the reactors which
keeps the cell in the perfect homogenous condition for better
transport of nutrients and oxygen to the desired product .
Buffles-to avoid vortex formation
to avoid vibration
to hold tubes in place
Sparger-to pass air into the vessel e.g. Porous sparger,
Nozzle sparger.
jacket-the jacket provide the annular area for the circulation
of constant temperature of water which keeps the
temperature of bioreactor at a constant value.
6. Antiform- Forming produced either by
agitation or by components used in the
medium like proteins. Foaming cause the
adhesion of cells to inner surface of vessel.
To avoid foaming antifoams are used like
pluronic f68, liquid paraffin and oil in some
cultures.
7. Stirred tank
Air lift reactors
Bubble column
Packed bed reactors
Fluidized bed reactor
Photobioreactor
8. Mixing medium: Mechanical Agitation
Large input required
Application: Waste water treatment
9. Continuous operation
Good temperature control
Good control
Simplicity of construction
Low operating (labor) cost
Easy to clean
10. Shear forces may kill cells
The need for shaft seals and bearings.
Size limitation by motor size, shaft length
and weight.
11. Mixing method: Air lift
Central Draught-tube
Up flowing stream and
down flowing stream
Homogenization of all
components
12. Simple design :with no moving parts or agitator for less
maintenance, less risk of defects.
No agitator shaft parts
Low Energy requirement VS stirred tank : Obviously
doesn’t need the energy for the moving parts (agitator
shaft).
Greater heat-removal VS stirred tank: At the Airlift
bioreactor it doesn’t need the heat plate to control the
temperature, because the Draught-Tube which is inside
the bioreactor can be designed to serve as internal heat
exchanger. It is difference to the Stirred tank bioreactor
that needs the heat coat or plate surrounding the tank to
make warm bioreactor. It is clear enough that the Airlift
bioreactor has greater heat-removal compare to Stirred
tank.
Very low cost
13. Greater air throughput and higher pressures
needed .
Extra foaming occur.
NO bubbles breaker .
14. These bioreactors do not have
any mechanical or otherwise
moving parts.
The upper section of the BC is
often widened to encourage gas
separation.
BCs require very little
maintenance or floor space and
have low operating costs
compared to other reactor
types.
15. Used in production of Baker’s yeast, beer &
vinegar.
Also used in aeration and treatment of waste
water.
In bubble column, the hydrodynamics and
mass transfer depend on the size of bubble
and how they are released from the sparger.
17. Require high pressure through sparger.
Occur extra foaming.
No bubble breaker.
18. Column with attached
biocatalyst
Pump is required to move
the fluid through packed
bed
Application: Waste water
treatment
19. Continuous operation
Low operation cost
No moving parts to wear out
Catalyst stays in reactor
Catalyst separation is easy
Effective at high temperature and pressure
20. Difficult to control pH by adding acids or
alkalis
Difficult to clean
Difficult to replace catalyst
Undesirable side reactions
21. When the packed beds are
operated in up flow mode
the bed expands at high
liquid flow rates due to
upward motion of particles
Energy is required
Suitable for a reaction
which carries enzymes
Waste water treatment
22. Uniform particle mixing
Uniform temperature gradient
Ability to operate reactor in continuous state
23. Increased reactor vessel size
Pumping requirements and pressure drop
Particle entrainment
Erosion of internal components
Pressure loss scenarios
24. Bioreactors specialized for fermentation that can
be carried out either by exposing to sunlight
Certain important compounds are produced by
employing photo-bioreactors e.g. astaxanthin
They are made up of glass or more commonly
transparent plastic
Photo-bioreactors are usually operated in a
continuous mode at a temperature in the range
of 25-40°C.
The organisms grow during day light while the
products are produced during night.
Microalgae and cyanobacteria
