Citric acid is commonly produced through submerged fermentation using Aspergillus niger fungus. There are three main methods - submerged culture fermentation, liquid surface culture fermentation, and KOJI fermentation. Submerged culture fermentation is the most common industrial process, using sugar, starch, or molasses in fermentors along with A. niger over 5-10 days. Citric acid is then recovered through calcium citrate precipitation, demineralization, and crystallization. Finally, citric acid has many uses as a preservative and acidulant in foods, cosmetics, pharmaceuticals, and other products.

1. Submitted To –
Dept.of Biotechnology
Submitted By –
Sonika Chouhan
M.Sc. III Sem

2. Content:
Organic Acid
Citric Acid
Methods Of Citric Acid Production &
Raw materials
KOJI Fermentation Process
Submerged Culture Fermentation Process
Liquid Surface Culture Fermentation Process
Fermentation Of Citric Acid by Microbes
Recovery and Purification
Uses Of Citric Acid

3. Organic Acid
• Organic acid are the organic compound with acidic
properties.
• The most common organic acids are the carboxylic
acids.
• Acidity is associated with their acid groups like-
carboxylic group (-COOH)
• Organic acid are the terminal products of glycolysis.
• For eg. Lactic acid
• These are the products of incomplete oxidation of
sugar.
Such as, , gluconic acid.

4. Citric Acid
• It is tricarboxylic acid, having
formula C6H8O7.
• It is first reported by “Carls
scheel” (1789-England) in
lemon juice.
• It occurs naturally in citric
fruits.
• It is a natural preservative and
used to add an acidic taste to
food & soft drinks.

5. conti
• It exists in a variety of fruits and vegetables ,
most conc. In lemon ,orange (7-8%).
• It is an intermediate of citric acid cycle.
• Commercially production of citric acid is
generally by submerged fermentation of
sucrose or molasses using the filamentous
fungus Aspergillus niger.

6. History :
• 1789 – Carl Scheele
• 1893 – Wehmer
• 1916 – Currie
• 1930 – some unit implanted in England ,
Germany for the commercial
production.

7. Methods Of Citric Acid Production
& Raw materials
Submerged Culture Fermentation Process
Liquid Surface Culture Fermentation Process
KOJI Fermentation Process1
2
3

8. Submerged Culture Fermentation Process
(Liquid Fermention)
• This is commonly used for citric acid production.
• It estimate about 80% .
• Less prize
• Small size
• High yield
• Low labour cost
Two types of fermentor are used-
Conventional stirrer
Tower fermentation

9. Fig. Liquid Fermentor

10. In this process
Raw material – sugar , starch
Treatment (if require)
Mycellia of aspergillus japonicum
flow about 15cm deep in tank
10% of fresh medium is required
It takes 5-10 days

12. Liquid Surface Culture Fermentation
Process
(surface fermentation)
• The first individual process for citric acid
production.
• It is introduce by “Des” in 1919
• Later “Chas” in 1923
• Sophisticated technique

13. Fig . Simple tray fermentor

14. In this process
• Liquid culture are incubated with spores
• Mycellia mat developed on the surface of
medium.
• It takes 24hrs.
• Crude sucrose, cane syrup & beet molasses
are used as carbon source.

15. KOJI Fermentation Process
(Solid state fermentation)
• It is an alternative method.
• This method is used first in JAPAN
• Aspergillus Niger Strain is used in this method.
• It is the simplest method .
• It can carried out using several raw
material(Table).

17. In this process
Substrate is moistened about 70%
acc.to capacity.
pH is maintained about 4.5-7.0
Temp. 28-30*C
It takes place in simple tray type
fermentor
Higher yield obtained ,without any
aeration and sporulation obseved
very little

19. Yeast
Candida tropicalis
Candida
Psuedotropicalis
Candida lipolytica
Moulds
Aspergillus niger
Penicillium
Mucor
trichoderma

20. • Recovery refers – to the high utilization of
product or ingredients, eliminating waste.

21. Fermented broth
Calcium citrate precipitation
Calcium sulphate
+ citric acid (impurities)
Demineralization
Evoporation and Crystallization
Citric acid crystal (Pure)
Calcium
hydroxide
Dil.H2so4
Treated
with
activated
carbon
charcoal

23. Uses Of Citric Acid
• In Food
Industries –
• It is used in fruits
• Jams
• Jellies
• Candies
• Packed food item
etc.

24. Cont…
• In cosmatics –
• It is used in shampo
• hair setting fluid
etc.

25. Cont…
• In pharmaceutical
products-
• It is used in syrups
• Tablets
• Health salts

26. Other uses
• In pharmacy –Blood transfusion
• It is used in leather-tanning
• In is used in home for vinegar,dying and
cleaning purpose.