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.
- Attenuated total reflection
- Bioprocess monitoring
- In situ measurement
- Mid-infrared spectroscopy
- Partial least squares regression
- Pichia pastoris
Dahlbacka, J., Weegar, J., von Weymarn, N., & Fagervik, K. (2012). On-line measurement of the substrate concentrations in Pichia pastoris fermentations using FT-IR/ATR. Biotechnology Letters, 34(6), 1009-1017. https://doi.org/10.1007/s10529-012-0868-9