Lecture No

Lecture Title : Fermentation – Glutamic
acid

Contents

➢ Production of Glutamic acid

Session Objectives

At the end of the session, student will be able to

➢ Explain the fermentation process of Glutamic acid

History of Glutamic acid

• The history of the first amino acid production dates back to 1908

when Dr. K. Ikeda, a chemist in Japan, isolated glutamic acid from

kelp, a marine alga, after acid hydrolysis and fractionation.

• He also discovered that glutamic acid, after neutralization with

castic soda, developed an entirely new, delicious taste.

• This was the birth of the use of monosodium glutamate (MSG) as a

flavour-enhancing compound.

History

• The breakthrough in the production of MSG was the isolation of a

specific soil-inhabiting gram-positive bacterium, Corynebacterium

glutamicum, by Dr. S. Ukada and Dr. S. Kinoshita in 1957.

• The successful commercialization of monosodium glutamate (MSG)

with this bacterium provided a big boost for amino acid production

and later with other bacteria like E. coli as well.

Glutamic acid

• It is an α-amino acid that is used by almost all living beings in the

biosynthesis of proteins.

• It is non-essential in humans, meaning the body can synthesize it. It

is also an excitatory neurotransmitter, in fact the most abundant

one, in the vertebrate nervous system.

• It serves as the precursor for the synthesis of the inhibitory gamma-

aminobutyric acid (GABA) in GABA-ergic neurons.

Uses

• It helps the nerve cells in the brain to send and receive information

from other cells.

• It may be involved in learning and memory.

• Glutamic acid is widely used in the production of monosodium

glutamate (MSG) which is commonly known as the ‘seasoning salt’.

• Monosodium glutamate is condiment and flavour-enhancing agent

• In hair loss and as anti ageing agent

Production
• Glutamic acid commercial production by microbial fermentation

provides 90% of world’s total demand, and remaining 10% is met

through chemical methods.

• Organism – Corynebacterium glutamicum

• Fermentors as large as 500 m3

• Media composition – carbohydrate (glucose, molasses, sucrose,

etc.), peptone, inorganic salts and biotin.

• Biotin concentration in the fermentation medium has a significant

influence on the yield of glutamic acid

Production
• Duration – 2-4 days

• The broth contains glutamic acid in the form of its ammonium salt.

Recovery
• The bacterial cells are separated and the broth is passed through a

basic anion exchange resin.
• Glutamic acid anions get bound to the resin and ammonia is

released.
• This ammonia can be recovered via distillation and reused in the

fermentation.
• Elution is performed with NaOH to directly form monosodium

glutamate (MSG) in the solution and to regenerate the basic anion
exchanger.

• From the elute, MSG may be crystallized directly followed by
further conditioning steps like decolourization and serving to yield a
food-grade quality of MSG.

Recovery

• α-ketoglutaric acid serves as the precursor of glutamic acid and the

conversion of the α- ketoglutaric acid to glutamic acid occurs in

presence of enzyme glutamic acid dehydrogenase.

• It has been found that if penicillin is added in the medium, the

glutamic acid production can be increased manifold.

Thank You
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