A fermenter is an apparatus that maintains optimal conditions for the growth of microorganisms.
The main function of the fermenter is to provide a controlled environment for the growth of a pure culture or of a defined mixture of microorganisms or animal cell to obtain the desired product.
Different parts of fermenter:-

1) Fermenter Vessel:

A suitable vessel is used to carry out the whole fermentation process. The vessel is capable of being operated aseptically and meet the containment requirements.

Glass vessel:

Glass vessels are smooth which makes it non toxic, corrosion proof. It also makes it easy to examine the interior of the vessel.

Stainless steel vessel:
Stainless steel is the most satisfactory material for large scale fermentations. These vessels can be sterilized in situ and hence have the capability to withstand pressure and corrosion.

2) Heating and cooling apparatus:
During fermentation process, heat is generated due to microbial activity and mechanical agitation.
Heat is generally provided by placing the fermenter in a thermostatically controlled bath, or by use of internal coils. To remove excess heat from the system, silicone jackets are used.

3) Sealing assembly:
Sealing assembly provides most satisfactory sealing to the stirrer shaft, which is required to provide agitation.

Three types seal assembly are used:

Packed gland seal: The shaft is sealed by several layers of packing rings of asbestos, pressed against the shaft by a gland.

Mechanical seal: The seal is consists of two parts, the stationary part in the bearing and the other rotating on the shaft. The two components are pressed together by springs.

Magnetic drives: It consists of two magnets, one driving and another driven.

4) Baffles:
Baffles are metal strips nearly one tenth of the vessel diameter and attached radially tp the wall. They are incorporated into agitated vessels of all sizes to prevent vortex and to improve aeration capacity.

5) Impeller:
Impeller is used for agitation. Agitation is required to ensure that a uniform suspension of microbial cells is acheived in an homogeneous nutrient medium.

6) Sparger;
Sparger is used for aeration. The purpose of aeration is to provide sufficient oxygen to the microoraganisms for metabolic requirements.

7) Feed ports:
Feed ports are slicone tubes connected to the nutrient reservoir. They are used to add nutrients and acid/alkali in the fermenter

8) Foam control:
Foam minimization is important in fermentation. Excessive foam results in wetting of filters thus resulting in contamination. A foam sensing and controll unit is used to control foam.

9) Valves:
Valves are required to controll the flow of gases and liquids in a variety of way. Five types of valves are used.

Globe valves: They are suotable for general purposes on stem or a water line for use when fully opened or fully closed. They do not regulate flow.

Butterfly valves: They are used in large diameter pipes operating under low pressure. They are not suitable for aseptic operation.

Ball valves: They are suitable for aseptic condition. the can handle mycelial broths and can be operated under high temperature.

Diaphragm valves: They are used for flow regulation and for stem services within pressure limits.

Safety valves:
Safety valve is incorporated in every air or stem vessel and pipe layout which is subjected to work under pressure. These valves ensures that the pressure never exceeds the safe upper limit of the specified value.http://www.oppapers.com/essays/Fermenter/446669

Fermenter 8.5 of 10 on the basis of 2049 Review.