Statistical optimization of medium for the production of recombinant hirudin from Saccharomyces cerevisiae using response surface methodology

An efficient fermentation medium producing a colourless product with high y ields has been developed for the production of recombinant hirudin from Sac charomyces cerevisiae. Response surface methodology was applied to optimize the medium constituents. A 2(5-1) fractional factorial central composite d esign has been chosen to explain the combined effect of the six medium cons tituents, viz. yeast extract, peptone, casamino acids, ammonium sulphate, p otassium phosphate and galactose, and to design a minimum number of experim ents. The optimized medium produced 65.3 mg/l of r-hirudin in shake flask c ulture, which is 35% higher than the unoptimized medium. The colour of the purified product was influenced by the colour intensity of culture supernat ant, which in turn depended upon the concentration of complex substrates us ed in the medium. The concentration of yeast extract has been reduced to 16 g/l in the optimized medium than other reported media containing 40 g/l ye ast extract. The colour intensity of culture supernatant obtained by the op timized medium was reduced by 60% from the reported media containing 40 g/l yeast extract. (C) 2000 Elsevier Science Ltd. All rights reserved.