1.
Y5E02 BIOPROCESS
TECHNOLOGY – Unit IV –
Acetic acid Production
Dr. S. SIVASANKARA NARAYANI
ASSISTANT PROFESSOR
DEPARTMENT OF MICROBIOLOGY
AYYA NADAR JANAKI AMMAL COLLEGE
SIVAKASI

2.
UniT -IV
• Microbial production technology: antibiotics (penicillin) - organic acids (citric acid and acetic acid) - vitamins (b12 and
riboflavin) - *enzymes (amylase) - alcoholic beverages (beer and wine). Single cell protein.
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3.
Acetic acid
• Acetic Acid is systematically named as ethanoic acid
• It is a colorless liquid organic compound.
• It has a pungent/ vinegar-like odor
• Vinegar is product of Acetic acid
• It has melting point 16 to 17°C; 61 to 62°F
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4.
History
• Acetic acid production is as old as wine making(10,000 years).
• In 3rd centaury Greek philosopher described how vinegar acted on metals to produce pigments useful in art.
• Ancient Romans boiled sour wine in lead pots to produce highly sweet syrup called sypa.
• In 8th centaury Persian chemist Jabir Ibn Hayyan concentrated Acetic acid from vinegar through distillation
processes.
• In 1847 German chemist Hermann Kolbe synthesized acetic acid from inorganic materials for first time.
• By 1910 most of the acetic acid was obtained from the from distillation of wood.
• At this time Germany is producing 10,000 tons of acetic acid.
• About 30% of which is used for the manufacturing of indigo dyes.
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Acetic acid bacteria
• Acetic acid bacteria is a gram-negative bacteria which oxidize sugar or ethanol
and produce acetic acid during fermentation.
• Acetic acid bacteria are rod-shaped & obligate aerobes.
• Pasteur in 1864 claimed that the transformation of wine into vinegar was due to
the veil of Mycoderma aceti on it surface pungency of acetic acid.
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Bacteria
• Acetic acid bacteria are commonly used for the production of acetic acid.
• The three important genera's are..
• 1 -Genus acetobacterium:
• The commonly used species are. Acetobacterium aceti Acetobacterium xylinum
• 2- Genus clostridium: the commonly used species is Clostridium
thermoaceticum…which is an anaerobic thermophile.
• 3-Acetic acid bacteria: Acetobacter and Gulocanobacter are commonly used,
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Raw materials
• Biomass Feedstock (beach wood, Silicon tube, sieving, wood chips)
• Ethanol is used as substrate.
• Microbes Acetic Acid Bacteria (Acetobacter aceti ) used as bio reactor
• Following substrates are commonly used.
• Ethanol
• Wine and whey
• Molasses
• Fermented grains
• malt and rice.
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Production
• Acetic acid is produced in following four steps.
• Conversion of starch to sugar by using amylases enzymes.
• Anaerobic conversion of sugars to ethanol by yeast fermentation.
• Conversion of ethanol to hydrated acetaldehyde.
• Finally by dehydrogenation acetic acid is produced by using aldehyde
dehydrogenase enzyme
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Biosynthesis
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Types
Acetic acid is produced industrially by following three methods..
• i. Orleans
• ii. Surface fermentation(trickling generation method).
• iii. Submerged fermentation methods.
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Orleans
• Old and traditional method.
• Slow but continuous processes.
• High grade vinegar is used as starter culture.
• Fermentation is done on large containers.
• Filled to two-third of its capacity.
• Wooden containers are laid down on their sides and holes are drilled at top and end
sides of barrel.
• Then ethanol is poured in to container using long necked funnels from top.
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Cont…
• Then add starter high grade vinegar.
• Ethanol convert in to acetic acid within five weeks.(35 days).
• Netting or screens are placed over holes to prevent insects getting entry in to barrels,
• The barrel's are allowed to sit for several months.
• The temperature is kept at 21-29 degree centigrade.
• Samples are taken periodically by inserting spigot in to side holes.
• When alcohol is converted to acetic acid, it drown off through spigot.
• About 15% liquid is left to blend with next batch.
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Trickling generation or Surface fermentation
• Also known as trickling system or germen processes.
• Most commonly used industrial method for production of acetic acid.
• Surface fermenter or barrel is filled with vinegar-moistened beech wood shavings.
• The substrate alcohol is poured from top of container and slowly drip down through
the shaving fillings.
• Oxygen is allowed to container through two routes.
• i. One through holes that have been punched into sides of vat.
• ii. Second through perforated bottom of vat.
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Cont…
• Air is introduced through holes by air-compressors.
• When alcohol reaches to bottom of vat , usually within a span of three days it has been
converted in to acetic acid.
• Following condition are kept under control.
• P.H range 2.5-3.2
• Temperature is kept between 20-30 degree C.
• 80-88% vinegar will be produced.
• ADVANTAGES : • Low cost • Ease of control. • High acetic acid concentration. • Less space
requirements.
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Submerged method
• This method is newer , faster and more efficient.
• For industrial processes, 10–18% ethanol and 5 times the nutrients used for submerged
fermentation are the starting conditions for fermentation.
• When the concentration of ethanol reaches 50–60% of the solution is removed and replaced
with fresh substrate containing 10–18% ethanol.
• Production plant is filled with large stainless steel containers called acetetors.
• Acetators are equipped with centrifugal pumps at bottom that will pump air bubbles in to
tank.
• As pump stirrers alcohol , the nutrients enhance the growth of acetobacter on oxygen bubbles
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Cont…
• Heat jackets keeps the temperature between 40 -42 degree centigrade.
• In 72 hours ethanol is converted to acetic acid
• The vinegar is piped from Acetator to plate and then frame to filtering machine.
• The stainless steel plates press alcohol through pipe filters to remove any sediment ,
usually about 3% of total product.
• The sediment is flushed in to drains while filtered vinegar move toward dilution
station.
• Advantages • Higher productivity. • Faster oxidation of ethanol. • Low cost due to
automation.
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Purification
• The isolation, purification and concentration of final product determine the
feasibility of the processes.
• A. Cell separation and cell lysis:
• the first operation is cell separation and cell lysis. Which can be done by using
following techniques.
• Cross-flow microfiltration
• Nano-filtration
• Electro.diaylasis “these techniques are useful to concentrate the glacial acetic acid”
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Application
• Common use:
• Used as solvent in different industrial processes.
• Used as an active ingredient in fragrance and perfumes.
• Used in production of synthetic fibers and textiles.
• Used to make ink and indigo dyes.
• Used in manufacturing of rubber and plastics.
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Cont..
• In medicinal industry:
• Acetic acid in the form of vinegar is used for preservation of food.
• Soothe sunburnt skin and to cure from jellyfish stings. •
• Effective tool for cervical cancer screening.
• In Health and hygiene: added in to.. • Hair conditioners • Detangles and
deodorant.
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Cont..
• House Hold cleaning:
• acetic acid in the form of white vinegar is used variety of cleaning tasks. •
• Removing smears and streaks from mirrors. •
• To descaling coffee making machines. •
• Remove urine odor and pet stain.
• Food flavoring: • Used as a condiment to produce pickles. • Used as a flavor
enhancer. • To preserve vegetables • In manufacturing of mint sauce and
production of rice.
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25.
clarification
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sivasan91@gmail.com
sivasan_sf549@anjaconline.org

26.
Questions to think
• What are the main things needed for acetic acid production?
• Acetic acid biosynthesis
• Steps involved in the production process of acetic acid
• Methods involved in the aceticacid production
• Pointout the use of acetic acid
• submerged and surface fermentation production of acetic acid - specify
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