5LECTURE STR-2
-
Upload
rajesh-guru -
Category
Documents
-
view
218 -
download
0
Transcript of 5LECTURE STR-2
-
8/7/2019 5LECTURE STR-2
1/20
P.V.S.YUGANDHAR M.Tech (
-
8/7/2019 5LECTURE STR-2
2/20
Temperature control system
pH control system
Cleaning and sterilization facilities
P.V.S.YUGANDHAR M.Tech ( Biotech)
-
8/7/2019 5LECTURE STR-2
3/20
Temperature probesHeat transfer systemTypically the heat transfer system will
use a "jacket" to transfer heat in or out ofthe reactor. The jacket is a shell whichsurrounds part of the reactor. The liquidin the jacket does not come in directcontact with the fermentation fluid.
P.V.S.YUGANDHAR M.Tech ( Biotech)
-
8/7/2019 5LECTURE STR-2
4/20
The jacket will typically be modified toencourage turbulence in the jacket andthus increase the heat transfer efficiency.An alternative to using jackets are coils.
Coils have a much higher heat transferefficiency than jackets. However coils takeup valuable reactor volume and can bedifficult to clean and sterilize.
P.V.S.YUGANDHAR M.Tech( Biotech)
-
8/7/2019 5LECTURE STR-2
5/20
In pilot and production scale reactors,
heating is typically only required
during the initial stages and finalstages of the fermentation as most
processes which occur during a
fermentation process, including the biological reactions (eg. growth)
chemical reactions
mixing
Which are exothermic
P.V.S.YUGANDHAR M.Tech ( Biotech)
-
8/7/2019 5LECTURE STR-2
6/20
The pH control system consists of
a pH probe
alkali delivery systemacid delivery system
The pH probe is typically steam
sterilizable.
P.V.S.YUGANDHAR M.Tech ( Biotech)
-
8/7/2019 5LECTURE STR-2
7/20
P.V.S.YUGANDHAR M.Tech( Biotech)
-
8/7/2019 5LECTURE STR-2
8/20
Small scale reactors are taken apartand then cleaned before being re-
assembled, filled and then sterilizedin an autoclave.
However, reactors with volumesgreater than 5 litres cannot be placedin an autoclave and sterilized. Thesereactors must be cleaned and
sterilized "in place". This process isreferred to "Clean in Place" and"Sterilize in Place". The commonlyused acronyms for these processes
are CIP and SIP.P.V.S.YUGANDHAR M.Tech ( Biotech)
-
8/7/2019 5LECTURE STR-2
9/20
CIP and SIP involves the complete
cleaning and sterilization of notonly the fermenter but also alllines linked to the internal
components of the reactor.S
team,cleaning and sterilizingchemicals, spray balls and highpressure pumps are used in these
processes. The process is usuallyautomated to minimize thepossibility of human error.
P.V.S.YUGANDHAR M.Tech ( Biotech)
-
8/7/2019 5LECTURE STR-2
10/20
Sterilization of the inlet air is undertaken to
prevent contaminating organisms fromentering the reactor. The exit air on the
other hand is sterilized to not only keep
contaminants from entering but also to
prevent organisms in the reactor from
contaminating the air.
A common method of sterilizing the inlet
and exit air is filtration. For small reactors
(with volumes less than 5 litres), disk
shaped hydrophobic Teflon membranes
housed in a polypropylene housing is used.
are used. Teflon is tough, reusable and does
not readily block.P.V.S.YUGANDHAR M.Tech ( Biotech)
-
8/7/2019 5LECTURE STR-2
11/20
For larger laboratory scale fermenters(up to 1000 litres), pleated membrane
filters housed in polypropylenecartridges are used.
Sterilization of the inlet and exit air inlarge bioreactors (> 10,000 litres) canpresent a major design problem.Large scale membrane filtration is a
very expensive process. Heat
sterilization is alternative option.Steam can be used to sterilize the air.With older style compressors, it waspossible to use the heat generated by
the air compression process toP.V.S.YUGANDHAR M.Tech ( Biotech)
-
8/7/2019 5LECTURE STR-2
12/20
P.V.S.YUGANDHAR M.Tech( Biotech)
-
8/7/2019 5LECTURE STR-2
13/20
A compressor forces the air intothe reactor. The compressor willneed to generate sufficientpressure to force the air through
the filter, sparger holes and intothe liquid.
Air compressors used for large
scale bioreactors typicallyproduce air at 250 kPa. The airshould be dry and oil free so as tonot block the inlet air filter orcontaminate the medium.P.V.S.YUGANDHAR M.Tech ( Biotech)
-
8/7/2019 5LECTURE STR-2
14/20
During sterilization the concept of
"maintaining positive pressure"will often be used. Maintainingpositive pressure means thatduring sterilization, cooling andfilling and if appropriate, thefermentation process, air must bepumped into the reactor.
Maintaining positive pressuremeans that during sterilization,cooling and filling and if
appropriate, the fermentationP.V.S.YUGANDHAR M.Tech ( Biotech)
-
8/7/2019 5LECTURE STR-2
15/20
P.V.S.YUGANDHAR M.Tech( Biotech)
-
8/7/2019 5LECTURE STR-2
16/20
P.V.S.YUGANDHAR M.Tech( Biotech)
-
8/7/2019 5LECTURE STR-2
17/20
The air sparger breaks the incoming air
into small bubbles.Various designs can be used such asporous materials made of glass or metal.However, the most commonly used type of
sparger used in modern bioreactors is thesparge ring:A sparge ring consists of a hollow tube in
which small holes have been drilled. Asparge ring is easier to clean than porous
materials and is less likely to block duringa fermentation.
The sparge ring must be located below theagitator and be approximately the same
diameter as the impeller.
P.V.S.YUGANDHAR M.Tech ( Biotech)
Sparger -- Oxygen delivery system -
-
8/7/2019 5LECTURE STR-2
18/20
P.V.S.YUGANDHAR M.Tech
( Biotech)
-
8/7/2019 5LECTURE STR-2
19/20
P.V.S.YUGANDHAR M.Tech
( Biotech)
-
8/7/2019 5LECTURE STR-2
20/20
P.V.S.YUGANDHAR M.Tech ( Biotech)