hii Presented on based on sterilization method in Bioprocess definition of sterilization there types importance of sterilization application of sterilization phy method ,chemical method ,mechanical method . Sterilization is the killing or removal of all microorganisms, including bacterial spores, which are highly resistant. Or It provides environment free from living micro-organisms . There are various methods of sterilization which are discussed below : Physical method Chemical method Biological method A . Physical Methods of Sterilization: Heat method of sterilization Filtration Radiation .

1. Methods of sterilization
Presented by : King Lovepreet Singh Grewal
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2. Fermentation
Fermentation
organism
Fermentation media
fermenter
Not sterilized
Media can get
contaminated
Lower yield of
product
Inhibit product
synthesis
Alter product
sterlization
Very important
Economic
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3. Sterilization is the killing or removal of all microorganisms, including bacterial spores,
which are highly resistant. Or It provides environment free from living micro-organisms .
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4. Methods of sterilization
There are various methods of sterilization which are discussed below :
A. Physical method
B. Chemical method
C. Biological method
A . Physical Methods of Sterilization:
1. Heat method of sterilization
2. Filtration
3. Radiation
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5. A. Physical Methods of Sterilization:
1. Heat method of sterilization
2. Filtration
3. Radiation
In heat sterilization process, This is the most common method of sterilization.
The heat used kills the microbes in the substance. The temperature of the heat and
duration of heating are the factors that affect the extent of sterilization the longer the
exposure to heat the better is the sterilization at a given temperature. As the
temperature of heat raises the time span required for sterilization decreases. Further,
the sterilization time increases with a decrease in temperature and vice-versa.
The heat method of sterilization is again of two types based on the type of heat used.
A) Moist heat methods
B) Dry heat methods
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6. Moist heat method of sterilization: Here heat is applied in the form of steam or just
boiling. This method includes techniques like:
1. Boiling
2. Pasteurization
By use of steam (Autoclave) Boiling is preferred for metallic devices like surgical
scissors, scalpels, needles, etc. Here substances are boiled to sterilize them.
Pasteurization is the process of heating the milk at a temperature of 6o degrees or 72
degrees 3 to four times. Here alternative heating and cooling kills all the microbes and
molds without boiling the milk.
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7. Dry heat methods:
Following methods are subjected for dry heat sterilization:
1. Flaming
2. Incineration
3. Hot air oven.
4. Radiation sterilization
•Flaming is the process of exposing metallic device like the needle, scalpels, and scissors
to flame for few minutes. The fire burns the microbes and other dust on the instrument
directly.
•Incineration is done especially for inoculating loops used in microbe cultures. The
metallic end of the loop is heated to red hot on the flame. This exposure kills all the
germs.
•Hot air oven is suitable for heat sterilization of dry material like powders, metal
devices, glassware, and other such laboratory stocks. Dry heat destroys microorganisms
by dehydration and oxidation or even incineration.
•Radiation This method involves exposing the packed materials to radiation for
sterilization. There are two types of radiations available for sterilization i.e.
a) non ionic radiation b) ionic radiation.
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8. Radiation
A. Non-ionic radiations are safe to the operator of sterilization, and they are like Ultra
Violet (UV) radiations, they can be used even at the door entrances to prevent
entry of live microbes through the air.
B. Ionizing radiation sterilization. They are powerful radiation and very useful for
sterilization. The operator needs to protect himself from exposure from these
radiations by use of special clothing. Ex: X-rays, γ-rays, etc.
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9. Filtration
In this method, liquids are filtered through bacterial filters to remove any microbes
present. This method is very effective for sterilization of heat sensitive liquids. The
chances of clogging and long time duration for the process to happen are
drawbacks.
For sterilization three types of filters are used:
•Membrane filters: These are thin filters which are made of cellulose. They can be
employed for online sterilization during injection by placing the membrane between
the syringe and needle. Used for sterilization of solvents, gasses.
•Seitz filters: These are made of asbestos or other material. They are pad like and
thicker than membrane filters. They do not rupture during filtration. But the
solution might get absorbed by the filter pad itself.
•Sintered glass filters: These are made of glass and hence do not absorb liquids
during filtration. The disadvantage is that they are very brittle and break easily.
•Candle filters: These are made of clay like diatomous mud. This special mud has
minute pores made by algae. The filters have many minute lengthy pores. The
microbes get stuck during their travel through the pore in the candle.
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10. Chemical Methods of Sterilization:
Gasses used for sterilization are very poisonous. The commonly used gas is ethylene
oxide with a combination of carbon-dioxide. Carbon dioxide is added to minimize the
chances of an explosion. Hydrogen peroxide, Nitrogen dioxide ,
Glutaraldehyde and formaldehyde solutions, Phthalaldehyde, and Peracetic acid are
other examples of chemicals used for sterilization.
Ethanol and IPA are good at killing microbial cells, but they have no effect on spores.
•Hydrogen Peroxide Sterilization, also known as hydrogen peroxide gas sterilization, is
a low temperature sterilization process commonly used to sterilize heat-sensitive
devices. A hydrogen peroxide sterilization process involves H2O2 vapor filling the
sterilizer chamber, contacting and sterilizing exposed device surfaces. Once the
sterilization cycle has completed, the vapor is vacuumed from the chamber and
converted to water and oxygen.
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11. Media sterilization -
The constituents of culture media, water and containers contribute to the
contamination by vegetative cells and spores.The media must be free from
contamination before use in fermentation. Sterilization of the media can be done by
various methods :
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12. Fermentaion media
Laboratory scale Industrial scale
Sterilization
Autoclaving Boiling Passing steam
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13. Batch sterilization
Advantages in batch sterilization
1. Most widely used .
2. Simple operation.
3. No additional materials are added.
4. The batch cooker method saves the production time, since the fermentor is
unoccupied between two fermentor runs.
Disadvantages in batch sterilization
1. More expensive heat requirements than continuous sterilization.
2. Best result occur in well-mixed closed vessels.
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14. Continuous sterilization
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Advantages Indirect heat exchanger
1. Less investment
2. Easy to maintain and clean
Disadvantages Indirect heat exchanger is
1. Heating may cause foams
2. Steam is in direct contact with medium, so medium should be enough
concentrated and steam should be free from any agent responsible for
anticorrosion

15. Important point
Generally fermentation media is steriliazed by autoclaving that is stem under pressure .
Some components present in media are heat sensitive , like vitamines , enzyme ,
amino acid ,
Such compound are sterilized by using bacteriological filter.
If the media are large amount the media is sterilization in batches by passing through
heat
Retention tubes.
Used the sterilized technique depends upon type of fermentation media used
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