Patent ID: 8450099

Claim:
A process for producing thioredoxin using at least one yeast selected from the group consisting of sake yeast, laboratory yeast and baker's yeast comprising: step (1) subjecting the yeast in a culture medium to a stress treatment to cause an extracellular release of thioredoxin, the stress treatment being selected from the group consisting of: (i) an ethanol stress treatment in which the yeast is stressed by being exposed to an environment with 10 to 30% by weight of ethanol, (ii) a pH-stress treatment in which the yeast is stressed by being exposed to an environment with an adjusted pH of 2 to 4, and (iii) an osmotic pressure stress treatment in which the yeast is added to a hypoosmotic solution; step (2) collecting protein containing thioredoxin from a fluid fraction; and step (3) subjecting the collected protein containing thioredoxin to a purification treatment to improve the purity of the thioredoxin.