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On-line monitoring and control of methanol concentration in shake-flask cultures of Pichia pastoris

TitleOn-line monitoring and control of methanol concentration in shake-flask cultures of Pichia pastoris
Publication TypeJournal Article
Year of Publication1997
AuthorsGuarna, MM, Lesnicki, GJ, Tam, BM, Robinson, J, Radziminski, CZ, Hasenwinkle, D, Boraston, A, Jervis, E, MacGillivray, RTA, Turner, RFB, Kilburn, DG
JournalBiotechnology and Bioengineering
Date PublishedNov
Type of ArticleArticle
ISBN Number0006-3592
Keywordsfermentation, GENE-EXPRESSION, methanol monitoring and control, methanol sensor, methylotrophic yeast, Pichia pastoris, PROTEINS, SEMICONDUCTOR GAS SENSORS, shake-flask cultures, TRANSFERRIN, YEAST

The methylotrophic yeast Pichia pastoris can be used to express recombinant genes at high levels under the control of the methanol-inducible alcohol oxidase 1 (AOX1) promoter. Accurate regulation of the methanol concentration in P. pastoris cultures is necessary to maintain induction, while preventing accumulation of methanol to cytotoxic levels. We developed an inexpensive methanol sensor that uses a gas-permeable silicone rubber tube immersed in the culture medium and an organic solvent vapor detector. The sensor was used to monitor methanol concentration continuously throughout a fed-batch shake-flask culture of a P. pastoris clone producing the N-lobe of human transferrin. The sensor calibration was stable for the duration of the culture and the output signal accurately reflected the methanol concentration determined off-line by HPLC. A closed-loop control system utilizing this sensor was developed and used to maintain a 0.3% (v/v) methanol concentration in the culture. Use of this system resulted in a fivefold increase in volumetric protein productivity over levels obtained using the conventional fed-batch protocol. (C) 1997 John Wiley & Sons, Inc.

URL<Go to ISI>://A1997XZ72800005