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Fermentation and oxygen transfer characteristics in recombinant human growth hormone production by Pichia pastoris in sorbitol batch and methanol fed‐batch operation
Author(s) -
Çalık Pınar,
İnankur Bahar,
Soyaslan Elif Ş.,
Şahin Merve,
Taşpınar Hatice,
Açık Eda,
Bayraktar Eda
Publication year - 2010
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.2292
Subject(s) - sorbitol , fermentation , pichia pastoris , chemistry , methanol , bioprocess , fed batch culture , food science , biochemistry , growth rate , pichia , chromatography , recombinant dna , biology , organic chemistry , paleontology , geometry , mathematics , gene
BACKGROUND: The influence of methanol feed rate on recombinant human growth hormone (rhGH) production by Pichia pastoris hGH‐Mut + in medium containing sorbitol was investigated at three different specific growth rates (µ), namely, 0.02 (MS‐0.02), 0.03 (MS‐0.03), and 0.04 (MS‐0.04). RESULTS: Increasing methanol feed rate above MS‐0.03 did not affect sorbitol consumption, showing that µ = 0.03 h −1 is a threshold limiting value, above which sorbitol utilization became independent of methanol feed rate. Moreover, when sorbitol was consumed, no further cell growth was observed. Increase in methanol feed rate triggered cell synthesis and the highest cell concentration was obtained at MS‐0.04 as 48 g L −1 ( t = 18 h); whereas, the highest rhGH production, 270 mg L −1 , was obtained at MS‐0.03 as a consequence of lower extracellular protease production and higher AOX activity (41 U g −1 CDW). Oxygen uptake rate increased with increasing µ, having the maximum value, 76.6 mmol m −3 s −1 , at MS‐0.04. K L a had a tendency to increase with µ, having a maximum value of 0.15 s −1 at MS‐0.04 ( t = 15 h). CONCLUSION: By considering rhGH concentration and oxygen transfer characteristics, the bioprocess can be improved by a two‐stage feeding strategy, operating at MS‐0.04 at the beginning of fermentation, and thereafter shifting to MS‐0.03. Copyright © 2009 Society of Chemical Industry