Patent ID: 7202060

Claim:
A process for producing L-leucine or L-isoleucine which comprises: culturing in a medium a recombinant strain of a microorganism belonging to the genus Escherichia, Serratia, Corynebacterium or Arthrobacter which has the ability to produce L-leucine or L-isoleucine and whose alanine-valine transaminase activity is enhanced by increasing its copy number of Escherichia coli DNA encoding alanine-valine transaminase in the cells of the microorganism, allowing L-leucine or L-isoleucine to form and accumulate in the culture, and recovering L-leucine or L-isoleucine from the culture, wherein the ratio of a by-product L-valine: L-leucine or L-isoleucine of the recombinant microorganism is reduced, compared to that of an unmodified microorganism.