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

A novel process using O-2-enriched air supply was used to suppress the C-te rminal proteolytic degradation of recombinant hirudin (r-hirudin) from Sacc haromyces cerevisiae. When dissolved O-2 was controlled above 20% saturatio n 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-2-en riched air giving above 40% saturation of dissolved O-2 suppressed the prot eolytic degradation and hence the formation of truncated forms of inactive r-hirudin until 60 h of fermentation.