Media for industrial fermentation process, substrates used as carbon, nitrogen sources, growth factors, inducers

1. R. NITHYA, M. Sc., M. Phil., (Ph. D)
ASSISTANT PROFESSOR
DEPARTMENT OF BIOTECHNOLOGY
SRI ADI CHUNCHNAGIRI WOMENS COLLEGE, CUMBUM
THENI DT, TAMIL NADU, INDIA

2. MEDIA FORMULATION
Micro-organisms used for fermentation process grow on or in growth medium which
satisfies the nutritional needs of microbes.
Complete analysis is needed to be done to establish the most favourable
medium for the growth of the microbe used for fermentation.
Formulating medium at lab scale can be done by adding main ingredients like
water,
carbon source,
nitrogen source,
minerals and other supplements
in pure form and in required quantities which supports the growth of the
microbe whereas, the same may not support the satisfactory growth of the same
organism at industrial level.

3. Following criteria need to be satisfied for the material to be treated
as medium at industrial level.
It should give maximum yield of product.
It should give minimum yield of undesired product.
It should be consistently available throughout the year.
It should be cheap.

4. MEDIA FOR INDUSTRIALL FERMENTATION
The media used for the growth of microorganisms in industrial fermentation must
contain all the elements in a suitable form for the synthesis of cellular substances as well as the
metabolic products.
In the laboratory, pure defined chemicals may be used for culturing microorganisms.
For industrial fermentations, undefined and complex substrates are frequently used
for economic reasons.
Cheaper substrates are advantageous since they minimize the production cost of the
fermented products.
Wastes from agriculture, and by products of other industries are generally
preferred.

5. TYPES OF MEDIA
The media used in fermentation processes may be
Synthetic or Crude
Synthetic media
Media with all the requisite constituents in a pure form in the desired
proportion represents synthetic media
Crude media
The non-synthetic media with naturally available source are better
suited for fermentation.
Crude media with an addition of requisite synthetic constituents is
ideal for good product yield in fermentation.

6. The most frequently used substrates for industrial
fermentation are
Carbon source
Nitrogen source
Vitamins and Growth factors
Minerals
Water
Chelators
Inducers and Elicitors
Inhibitors
Antifoams

7. Medium component Defined Component Un-defined component
Carbon source Glucose, Fructose,
Glycerol, Xylose,
Sucrose, Starch
Molasses, Meat extract,
Peptone, Plant extracts and
Materials (Cellulosic,
lignoncellulosic and
hemicellulosic materials,
Starch
complex, etc…)
Nitrogen source Ammonium and
Nitrate Salts
Yeast extract, Amino acid
complex, Casein
Phosphate Mono and di-
phosphate salts
In traces of complex C- and N
sources
CULTIVATION MEDIA

8. Medium component Defined Component Un-defined component
Sulphur Ammonium and
Magnesium sulphate
In traces of complex C-
and N sources
Magnesium Mainly Magnesium
sulphate In
In traces of complex C-
and N sources
Mn, Mo, Fe, Zn, etc.. In form of Inorganic salts In traces of complex C-
and N sources
Vitamins and Growth
factors
Added in pure form of
vitamin and
growth factors
preparation
Yeast extract, and may
found
also as traces in some C-
and
N-sources
CULTIVATION MEDIA

9. SUBSTRATES USED AS CARBON SOURCES
Carbohydrates – most predominant source of energy in
fermentation industry
Refined & pure
Carbohydrates – glucose or sucrose are rarely used for
economic reasons.
Substrates such as
Molasses
Malt extract
Starch, dextrin and cellulose
Whey
Methanol and Ethanol used as carbon source

10. MOLASSES
- By product of sugar industry
- cheapest sources of carbohydrates
- Sugarcane molasses (sucrose 48%)
- Sugar beet molasses (sucrose 33%)
- Molasses also contains
nitrogenous substances
Vitamins
Trace elements
- Hydrol molasses – byproduct of glucose production from corn used as a
fermentation substrate.

11. MALT EXTRACT
Malt extract - an aqueous extract of malted barely contains
80% Carbohydrates (glucose, fructose, sucrose, maltose).
4.5% Nitrogen compounds (proteins, peptides, amino acids, purines,
pyrimidines)

12. STARCH, DEXTRIN AND CELLULOSE
- The polysaccharides – starch, dextrin and cellulose
can be metabolized by microorganisms.
- Frequently used for industrial production of alcohol.
- low cost
- Widely available

13. WHEY
- Byproduct of dairy industry
- Good source of carbon.
- Used for the production of
Alcohol
Single cell protein
Vitamin B12
Lactic acid and
Gibberellic acid

14. METHANOL AND ETHANOL
Some microbes utilize methanol or ethanol
as carbon source.
Methanol - cheapest source – utilized by
only a few bacteria and yeasts.
Used for the production of single
cell protein
Ethanol - Expensive
Used for Acetic acid production

15. SUBSTRATES USED AS NITROGEN SOURCES
Inorganic nitrogen sources
Ammonium salts
Free ammonia
Organic nitrogen sources
Urea
Corn steep liquor
Yeast extracts
Soy meal
Peptones

16. INORGANIC NITROGEN SOURCES
Ammonium salts or free ammonia – cheap inorganic nitrogen
sources
All the microorganisms are not capable of utilizing them.
Hence their use is limited .

17. ORGANIC NITROGEN SOURCES
UREA
Good source of nitrogen
Cheapest source of organic forms of nitrogen

18. CORN STEEP LIQUOR
-This is formed during starch
Production from corn.
- Rich in nitrogen(4%)
- It is rich in several amino acids
Alanine, valine, methionine,
Arginine, threonine, glutamate.

19. YEAST EXTRACTS
It contains 8% nitrogen and are rich
in amino acids, peptides and vitamins.
It is produced from baker’s
Yeast through autolysis (at 50-550C) or
Through plasmolysis
(high concentration of NaCl).
Very good sources for many industrially
important microorganisms

20. SOY MEAL
After extracting the soy bean
oil from the soy bean seeds,
the left out residue is soy meal.
It is rich in proteins(50%)
Carbohydrates (30%)
It is used in antibiotic
production

21. PEPTONES
- Protein hydrolysates
- Source of peptones include
meat, soy meal, peanut seeds
cotton seeds and sunflower seeds
- Proteins include casein, gelatin and keratin
can be hydrolyzed to yield peptones.
- Peptone derived from animal sources - more nitrogen content than plant sources
- Expensive, not widely used in industries

22. SOURCES OF GROWTH FACTORS
Some of the microorganisms are not capable of synthesizing one or more
growth factors such as vitamins.
Vitamins are expensive in pure form, hence crude sources are preferred.
Yeast extract is a rich source of almost all growth factors.

23. MINERALS
All microorganisms require certain mineral elements for growth and
metabolism.
Major elements - magnesium, phosphorous, potassium, sulphur,
calcium and chlorine
Minor elements - cobalt, copper, iron, manganese, molybdenum
and zinc are added.
E.g. Corn steep liquor contains a wide range of minerals that will satisfy the
minor and trace mineral needs.

24. WATER
• All fermentation processes, except SSF, require vast quantities of water.
• Important for ancillary services like heating, cooling, cleaning and rinsing.
• Important factors to consider when assessing suitability of a water supply are:
pH, dissolved salts and effluent contamination.
• Water is hard , it is treated to remove salts such as calcium carbonate, iron
and chlorine.
• For plant and animal cell culture, the water must be
highly purified.
Reuse of water is important - It reduces water cost by 50%

25. CHELATORS
Metal binders – It is a chemical compound that react with metal ions to form a stable
water soluble complex.
Metals are distributed in chelated form
Some chelating agents are added to form complexes with metal ions which are
gradually utilised by microorganisms.
Examples :EDTA, Citric acid, phosphates.
Phosphates are widely used as a chelating agent .
Used as a required quantity otherwise it will inhibit the growth of microorganism.

26. INDUCERS AND ELICITORS
 If product formation is dependent upon the presence of a specific inducer
compound or a structural analogue, it must be incorporated into the culture
medium or added at a specific point during the fermentation.
 The majority of enzymes of industrial interest are inducible. Inducers are
often substrates such as starches or dextrin's for amylase.
 In plant cell culture the production of secondary metabolites, such as
flavanoids and terpenoids can be triggered by adding elicitors.

27. INDUCERS

28. OXYGEN
• Supplied in the form of air containing about 21% (v/v) oxygen
• Oxygen requirements may vary widely depending upon the carbon source.
• The specific oxygen uptake rate of a microorganism increases with increase
in the dissolved oxygen concentration up to a certain point referred to as the
critical level.
• Maximum biomass production is achieved by satisfying the organism’s
maximum specific oxygen demand by maintaining the dissolved oxygen
concentration greater than the critical level.

29. INHIBITORS
Inhibitors are used to redirect metabolism towards the target product and
reduce formation of other metabolic intermediates.
Inducers are added at a certain point to prevent further metabolism of the target
product.
An example of an inhibitor specifically employed to redirect metabolism is
sodium bisulphite

30. INHIBITORS

31. ANTIFOAMS
• Antifoams are necessary to reduce foam formation during fermentation.
• Foaming is largely due to media proteins that become attached to the air-broth
interface where they denature to form a stable foam “skin” that is not easily
disrupted.
• If uncontrolled the foam may block air filters, resulting in the loss of aseptic
conditions; the fermenter becomes contaminated and Microorganisms are released
into the environment

32. ANTIFOAMS
- Alcohols; stearyl and octyl decanol
- Esters
- Fatty acids and derivatives (glycerides) linseed oil, cotton seed
oil, olive oil, castor oil, sunflower oil, rapeseed oil and cod
liver oil.
- Silicones
- Sulphonates
- Alkaterge C, oxazaline, poly-propylene glycol.