Friday, 2 December 2011

L-Lysine Production

L-Lysine Fermentation
Out of 20 naturally occurring amino acids, L- lysine is one of 9 essential amino acids and commercially important amino acids. It is mainly used as feed additive in the animal feed industry; mixed with various common livestock such as cereals which do not contain sufficient levels of L-Lysine for the livestock’ nutritional requirements, in especially monogastric animals like broilers, poultry and swine and as a supplement for humans and improving the feed quality by increasing absorption of other amino acids.
L-Lysine can be produced by chemical or biochemical method; whichever is more economic. Gram+ve cyanobacteria strains like Corynebacterium glutamicum, Brevibacterium flavum are used for industrial production.

Fermentation Medium:
Apart from physical parameters like pH, Agitation and aeration rate and temperature; media composition is very important factor.
The seed culture to be prepared includes:
Glucose: 20g                                                     
Peptone: 10g                                                 
Meat extract: 5g                                               
Sodium chloride: 2.5g in 1 litre of tap water     
Seed culture obtained is reinoculated for 2nd seed culture in media containing:
Molasses: 200g                                                   
Soy protein hydrolysate 18g in 1L tap H2O        
Above culture is reinoculated with B.flavum     
Acetate is used as C source                                 
After obtaining first and second media production media is used which includes:
Cornsteep liquor
Ammonium sulphate
Incubation for 72 hours at 28 degrees
Fraction of lysine fermentation broth is obtained by any suitable, Methods such as Ultrafiltration or Centrifugation. In order to overcome difficulties of high viscosity in culture broth; filterability can be improved by adding a mineral acid like conc. H2SO4 and then heat the culture broth at 100degrees for at least 5 minutes. The resulting product is L lysine.

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