Different types of fermenters/Bioreactors

1. Bioreactors-:
 By
 Harinatha Reddy A
 Department of Biotechnology
 Christ University

2. Introduction:
 The heart of fermentation technology is the fermenter.
 Bioreactor is a device in which the organisms are cultivated and
motivated to form the desired product.

3. A bioreactor should provide:
 Agitation (for mixing of cells and medium).
 Aeration (aerobic fermentors); for O2 supply.
 Regulation of factors: like TMP, pH, pressure, nutrient feeding.
 Provide aseptic environment.

4. Types of Bioreactors:
 Based on design and function the bio reactors, there are different
types of bioreactors.
 Continuous stirred tank reactors,
 Airlift bioreactors,
 Bubble colum bioreactors,
 Fluidized bed bioreactors,
 Packed bed bioreactors,
 Tower reactors,
 Drum reactors,
 Photobioreactors.

5. 1. Continuous stirred tank reactors (CSTRs):
• CSTRs are open or closed systems , the contents of the
fermenters are well mixed by agitators and remove
continuously form fermenter.

6. Continuous stirred tank reactors CSTRs :
 A continuous stirred tank bioreactor
consists of a cylindrical vessel (Made up
of steel).
 CSTRs contain central shaft attached to
motor that supports one or more
agitators (impellers).
 The shaft is fitted at the bottom of the
bioreactor.
 The number of impellers is variable and
depends on the size of the bioreactor.

7.  In CSTRs the air is added to the culture medium through a
device called sparger.
 The spargers and impellers (agitators) provide better gas
distribution system throughout the vessel.

8. Applications:
 CSTRs are usually applied in waste water treatment processes.
 CSTRs used for maintenance of animal cell cultures.
 CSTRs provide good mixing of the contents.
 CSTRs provide high dilution rate.

9. 2. Bubble Column Bioreactors:
 A continuous stirred tank
bioreactor consists of a
cylindrical vessel (Made up of
steel).
 In the bubble column bioreactor,
the air or gas is introduced at
the base of the column through
pipes or plates, or metal micro
spargers

10. Applications:
 Bubble column reactors are used in various types of chemical
reactions like oxidation reactions.
 For the cultivation of algae bioreactor.

11. 3. Airlift Bioreactors:
 The internal circulation and mixing of
medium are achieved by bubbling air.
 In the airlift bioreactors, the medium of the
vessel is divided into two interconnected
zones by means of a baffle or draft tube.
 Inner gassed region ( Riser) here gas is
pumped.
 Outer un-gassed region ( Down comer)

12. There are two types of airlift bioreactors:
 Internal-loop airlift bioreactor.
 External loop airlift bioreactor.

13. Internal-loop airlift bioreactor.
 Internal-loop airlift bioreactor has a single
container with a central draft tube.
 The air is pumped form the bottom of the central
draft tube that creates interior liquid circulation
channels.
 These bioreactors are simple in design, and
provide circulation at a fixed rate for
fermentation.

14. External loop airlift bioreactor:
 External loop airlift bioreactor possesses an
external loop so that the liquid circulates
through separate independent channels.
 In general, the airlift bioreactors are more
efficient than bubble columns, particularly for
more denser suspensions of microorganisms.
 This is mainly because in these bioreactors, the
mixing of the contents is better compared to
bubble columns.

15. Applications:
 Airlift bioreactors are commonly employed for aerobic
bioprocessing technology.
 Airlift bioreactors used for methanol production, waste water
treatment, single-cell protein production.

16. Fluidized Bed Bioreactors:

17. Fluidized Bed Bioreactors:

18.  Fluidized bed bioreactor is comparable to bubble column
bioreactor.
 The top of the bioreactor is expanded and consists of narrow bottom
to reduce the velocity of the fluid.

19.  In fluidized bioreactors solids (Immobilized enzymes or
microorganism) are retained in the reactor while the liquid
flows out.
 In this bioreactors immobilized enzymes, immobilized
microorganisms are used.

20.  For an efficient operation of fluidized beds, gas is spared to create
a suitable gas-liquid-solid fluid bed.
 The suspended solid particles (density) are not too light or high
other wise they may float way along with fermented culture.

21. Advantages:
 Uniform Particle Mixing.
 Ability to Operate Reactor in Continuous State.
 Commonly used in Wastewater treatment.
 Petroleum processing.

22. Packed Bed Bioreactors:

23.  A bed of solid particles, with biocatalysts packed in a column
constitutes a packed bed bioreactor.
 The solids used may be porous or non-porous gels.
 A nutrient broth flows continuously over the immobilised
biocatalyst.

24.  The products obtained in the packed bed bioreactor are released
into the fluid and removed.
 While the flow of the fluid can be downward, down flow under
gravity is preferred.

25. Advantage:
 The packed bed bioreactors do not allow accumulation of the end
products to any significant extent.
Disadvantage:
 Because of poor mixing of nutrients throughout the fermenter.
 It is rather difficult to control the pH of packed bed bioreactors
by the addition of acid or alkali.

26. Applications:
 Anaerobic packed-bed bioreactor for the production of hydrogen
and organic acids.
 Packed-bed bioreactors for mammalian cell culture.
 Enzymatic conversion of penicillin to 6-amino penicillanic acid.

27. Photo-Bioreactors:
Centrifugal pumps or airlift pumps.

28.  These are the bioreactors specialised for fermentation that can be
carried out either by exposing to sunlight or artificial illumination.
 The outdoor photo-bioreactors are preferred.
 Certain important compounds are produced by employing photo-
bioreactors e.g., carotenes and xanthophyll's.

29.  They are made up of glass or more commonly transparent plastic.
 The array of glass tubes or flat panels constitute light receiving
systems (solar receivers).
 The culture and nutrients and medium can be circulated through
the glass tubes or solar receivers by methods such as using
centrifugal pumps or airlift pumps.

30.  Photo-bioreactors are usually operated in a continuous mode at
a temperature in the range of 25-40°C.
 Microalgae and cyanobacteria are normally used.
 The organisms grow during day light while the products are
produced during night.

31. Tower Bioreactors:

32. Tower Bioreactors:

33.  Tower fermenters are modified stirred tank reactors that do not
require agitation.
 Therefore, they lack shafts, motor, impellers (Agitators) and blades.
 But it contain spargers to pump air in to bioreactor.


34.  They consist of a long cylindrical vessel with an inlet at the
bottom, an exhaust nutrients at the top, and a jacket to control
temperature.

35. Applications:
 The tower fermenters easy to construct.
 Tower fermenters have found applications in continuous
fermentation of beer and SCP.

36. Rotary drum reactor:

37.  In this bioreactor only 40 % cylindrical drum is filled with
nutrients and rotated by means of rollers or motor.
 They are equipped with an inlet and outlet for circulation of
humidified air and often contain baffles to agitate the
contents.

38. Advantages of Rotary Drum Reactor:
 High oxygen transfer.
 Good mixing facilitates better growth.
 It is particularly suitable for the cultivation of the plant cell
cultures.

39. Disadvantages of Rotary Drum Reactor:
 Poor yield.
 Their main disadvantage is that the drum is not filled to
capacity (only 30% or 40% capacity) other wise mixing is
inefficient.

40. THANK U……….