Process for producing amino acids

Abstract

The present invention provides: a process for producing an amino acid which comprises adding crystals of the amino acid having an average particle size of 1 to 120 μm to a medium so that the concentration of the crystals of the amino acid becomes 0.5 g/l or more, culturing a microorganism having the ability to produce the amino acid in the medium, allowing crystals of the amino acid to form and accumulate in the medium, and recovering the crystals of the amino acid from the culture; and a process for producing an amino acid which comprises adding crystals of the amino acid to a medium so that the total surface area of the crystals of the amino acid in the medium becomes 0.02 m 2 /l, culturing a microorganism having the ability to produce the amino acid in the medium, allowing crystals of the amino acid to form and accumulate in the medium, and recovering the crystals of the amino acid from the culture.

The invention claimed is: 
     
       1. A process for producing an amino acid, which comprises:
 culturing a microorganism having an ability to produce the amino acid in a medium, 
 adding crystals of the amino acid having an average particle size of 1 to 120 7 to 50 μm to a the medium at some time after the amino acid concentration in the medium reaches the saturation solubility and before crystals of the amino acid deposit in the medium so that the concentration of the crystals of the amino acid becomes 0.5 g/l or more, 
 culturing a the microorganism having the ability to produce the amino acid in the medium, 
 allowing the crystals of the amino acid to form grow to crystals of the amino acid having an average particle size of 30 μm or more and accumulate in the medium, and 
 recovering the crystals of the amino acid from the culture by separating the microorganism producing the amino acid and the accumulated crystals of the amino acid based on the difference in particle size or specific gravity between them. 
 
     
     
       2. A process for producing an amino acid, which comprises:
 culturing a microorganism having an ability to produce the amino acid in a medium, 
 adding crystals of the amino acid having an average particle size of 7 to 50 μm to a the medium at some time after the amino acid concentration in the medium reaches the saturation solubility and before crystals of the amino acid deposit in the medium so that the total surface area of the crystals of the amino acid in the medium becomes 0.02 m 2 /l or more, 
 culturing a the microorganism having the ability to produce the amino acid in the medium, 
 allowing the crystals of the amino acid to form grow to crystals of the amino acid having an average particle size of 30 μm or more and accumulate in the medium, and 
 recovering the crystals of the amino acid from the culture by separating the microorganism producing the amino acid and the accumulated crystals of the amino acid based on the difference in particle size or specific gravity between them. 
 
     
     
       3. The process according to  claim 1  or  2 , wherein the crystals of the amino acid added are those having a specific surface area of 0.06 m 2 /cm 3  or more. 
     
     
       4. The process according to  claim 3 , wherein the crystals of the amino acid formed and accumulated have an average particle size of 15 μm or more. 
     
     
       5. The process according to  claim 3 , wherein the amino acid is L-glutamine, L-valine, L-leucine, L-isoleucine, L-phenylalanine, L-tyrosine or L-tryptophan. 
     
     
       6. The process according to  claim 4 , wherein the amino acid is L-glutamine, L-valine, L-leucine, L-isoleucine, L-phenylalanine, L-tyrosine or L-tryptophan. 
     
     
       7. The process according to  claim 1 , wherein the amino acid is L-glutamine, L-valine, L-leucine, L-isoleucine, L-phenylalanine, L-tyrosine or L-tryptophan. 
     
     
       8. The process according to  claim 2 , wherein the amino acid is L-glutamine, L-valine, L-leucine, L-isoleucine, L-phenylalanine, L-tyrosine or L-tryptophan. 
     
     
       9. The process according to  claim 4 , wherein the crystals of the amino acid formed and accumulated have an average particle size of 20 μm or more. 
     
     
       10. The process according to  claim 9 , wherein the crystals of the amino acid formed and accumulated have an average particle size of 30 μm or more. 
     
     
       11. The process according to claim  10  3, wherein the crystals of the amino acid formed and accumulated have an average particle size of 40 μm or more. 
     
     
       12. The process according to  claim 11 , wherein the crystals of the amino acid formed and accumulated have an average particle size of 50 μm or more. 
     
     
       13. The process according to  claim 12 , wherein the crystals of the amino acid formed and accumulated have an average particle size of 60 μm or more. 
     
     
       14. The process according to claim 11, wherein the amino acid is L-glutamine, L-valine, L-leucine, L-isoleucine, L-phenylalanine, L-tyrosine or L-tryptophan. 
     
     
       15. The process according to claim 12, wherein the amino acid is L-glutamine, L-valine, L-leucine, L-isoleucine, L-phenylalanine, L-tyrosine or L-tryptophan. 
     
     
       16. The process according to claim 13, wherein the amino acid is L-glutamine, L-valine, L-leucine, L-isoleucine, L-phenylalanine, L-tyrosine or L-tryptophan.