Improvement of recombinant hirudin production by controlling NH4+ concentration in Pichia pastoris fermentation
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- Yang, J., Zhou, X. & Zhang, Y. Biotechnology Letters (2004) 26: 1013. doi:10.1023/B:BILE.0000030049.75092.95
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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.