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Updated: Aug 23, 2026

Expression of Recombinant Proteins in the Methylotrophic Yeast Pichia pastoris
Published on: February 25, 2010
Improvement of recombinant hirudin production by controlling NH4+ concentration in Pichia pastoris fermentation
Jizhong Yang1, Xiangshan Zhou, Yuanxing Zhang
1State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, P.R. China.
Abstract:
In recombinant Pichia pastoris fermentation for hirudin production in a 5 l fermenter, a new strategy was explored to match the short fermentation time at low NH4+ concentration with decreased hirudin degradation at high NH4+ concentration. A combination of a defined medium containing initial 0.025 m NH4+ with NH4+ addition up to 0.6 m in the growth phase was achieved in both the improvement of hirudin production and the repression of hirudin degradation. Intact and total hirudin reached 2.63 g l(-1) and 4.25 g l(-1), respectively.
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