African Journal of
Biotechnology

  • Abbreviation: Afr. J. Biotechnol.
  • Language: English
  • ISSN: 1684-5315
  • DOI: 10.5897/AJB
  • Start Year: 2002
  • Published Articles: 12227

Full Length Research Paper

On-line methanol sensor system development for recombinant human serum albumin production by Pichia pastoris

Panchiga Chongchittapiban
  • Panchiga Chongchittapiban
  • Department of Chemical Engineering, Faculty of Engineering, King Mongkut's University of Technology Thonburi (KMUTT), 126 Pracha-utid Road, Bangmod, Toongkru, Bangkok 10140, Thailand.
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Jorgen Borg
  • Jorgen Borg
  • Pilot Plant Development and Training Institute (PDTI), 49 Soi Tientalay 25, Bangkhuntien-Chaithalay Road, Thakham, Bangkhuntien, Bangkok 10150, Thailand.
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Yaowapha Waiprib
  • Yaowapha Waiprib
  • Department of Fishery Products, Faculty of Fisheries, Kasetsart University (KU), 50 Ngam Wong Wan Road, Ladyaow, Chatuchak, Bangkok 10900, Thailand.
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Jindarat Pimsamarn
  • Jindarat Pimsamarn
  • Department of Chemical Engineering, Faculty of Engineering, King Mongkut's University of Technology Thonburi (KMUTT), 126 Pracha-utid Road, Bangmod, Toongkru, Bangkok 10140, Thailand.
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Anan Tongta
  • Anan Tongta
  • Division of Biotechnology, School of Bioresources and Technology, King Mongkut’s University of Technology Thonburi (KMUTT), 49 Soi Tientalay 25, Bangkhuntien-Chaithalay Road, Thakham, Bangkhuntien, Bangkok 10150, Thailand.
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  •  Received: 23 November 2015
  •  Accepted: 30 June 2016
  •  Published: 19 October 2016

Abstract

An on-line methanol sensor system was developed using a methanol probe, methanol sensor unit and peristaltic pump. The system was commanded using data acquisition (DAQ) and LabVIEW software. Calibration of the methanol sensor system was done in a medium environment with yeast cells during cells adaptation to methanol metabolism after glycerol feeding was stopped. The correlation equations between voltage output signal from the methanol sensor unit and residual methanol in culture broth were created with third order polynomial regression. This developed system was implemented for on-line methanol control in recombinant human serum albumin (rHSA) protein production by P. pastoris KM71 at methanol levels of 4 and 10 g/l with controlled fluctuations at 13.0 and 11.3% of oscillation, respectively. The accumulated amounts of recombinant protein from two levels of methanol concentration controls (4 and 10 g/l) were similar but the proteins were produced at a different rate related with methanol concentration in the broth. Therefore, the control at 10 g/l methanol had a higher production rate (0.53 mg-protein/g dry-cell×h) than 4 g/l methanol control (0.38 mg-protein/g dry-cell×h) as it reached the maximum protein concentration in a shorter time, even though its cell yield was less than that of 4 g/l methanol control. At the end of the experiments, the high cell density environment caused both cell and protein reduction by cell autolysis and protease degradation. However, the protein decrease could be prevented by taking protein induction at a low temperature and a pH where protease does not function.

 

Key words: Methanol monitoring, methanol sensor, on-line methanol, Pichia pastoris, recombinant human serum albumin.