On-line measurement of the substrate concentrations in Pichia pastoris fermentations using FT-IR/ATR

John Dahlbacka (Corresponding Author), Jan Weegar, Niklas von Weymarn, Kaj Fagervik

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12 Citations (Scopus)


The glycerol and methanol concentrations in Pichia pastoris fermentations were measured on-line using Fourier transform infrared spectroscopy and an attenuated total reflection probe. Partial least squares regression was used to obtain calibration models. The models were regressed on synthetic multi-component spectra and semi-synthetic fermentation broth spectra. These were obtained by spectral addition. The accuracy for the on-line measurement of glycerol, given as standard error of prediction (SEP), was determined to 0.68 g/l, and the SEP of methanol was 0.13 g/l. We show how reliable calibration models are obtained relatively effortlessly by replacing extensive sampling from the reactor with simple mathematical manipulations of the model regression spectra.
Original languageEnglish
Pages (from-to)1009-1017
JournalBiotechnology Letters
Issue number6
Publication statusPublished - 2012
MoE publication typeA1 Journal article-refereed


  • Attenuated total reflection
  • Bioprocess monitoring
  • In situ measurement
  • Mid-infrared spectroscopy
  • Partial least squares regression
  • Pichia pastoris


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