METHOD OF EXTRACTING L-LYSINE FROM CULTURE FLUID Russian patent published in 2011 - IPC C12P13/08 C07C227/40 C07C229/26 

FIELD: chemistry; biochemistry.

SUBSTANCE: invention pertains to biotechnology. Disclosed is a method of extracting L-lysine from culture fluid. Biomass-free culture fluid is acidified to pH 1.9-2.3. Lysine is sorbed from the obtained solution on a sulphocationite strongly cross-linked with polystyrene to saturation or close to saturation state. The cationite is washed from said solution with water at temperature 70-85°C and consumption of desalinated water is equal to 1.1-1.3 times the volume of the ionite layer. Elution is carried out with 5% ammonia solution. The lysine-containing fraction is collected when pH 6-7 is attained. A sulphur-containing antioxidant is added to the lysine-containing fraction in amount of 0.28-0.43%. Primary vacuum-evaporation of the fraction is carried out with concentration of the solution 2.3-2.8 times. The obtained concentrate is neutralised with hydrochloric acid. Said concentrate is adsorptionally clarified on a macroporous weakly basic anionite of the condensation type. Secondary vacuum evaporation is carried out. Lysine monochlorohydrate is then crystallised. The crystals are separated from the mother solution and dried at temperature 85-90°C.

EFFECT: process of extracting L-lysine is characterised by high purity of the crystalline product of 99,1-100% with level of irreversible loss lower than 6,1%.

2 cl, 2 ex