Suppression of proteolytic degradation of recombinant hirudin from Saccharomyces cerevisiae using the O sub(2)-enriched air

A novel process using O sub(2)-enriched air supply was used to suppress the C-terminal proteolytic degradation of recombinant hirudin (r-hirudin) from Saccharomyces cerevisiae. When dissolved O sub(2) was controlled above 20% saturation level using normal air, inactive forms of C-terminally truncated hirudin were observed in culture broth from 48 h of fermentation. The use of O sub(2)-enriched air giving above 40% saturation of dissolved O sub(2) suppressed the proteolytic degradation and hence the formation of truncated forms of inactive r-hirudin until 60 h of fermentation.