IR-spectroscopy and PLS modelling for advanced bio-process monitoring: simultaneous and rapid sensing of various components

Industry is increasingly focusing on the development of more efficient and less time-consuming methods to monitor and control their fermentation processes at optimal conditions. Here, Infrared (IR) Spectroscopy is among the most promising techniques for on-line or at-line applications. Fitted to the fermenter by fiber optical probes, IR spectroscopy coupled with mathematical models relates the spectra to various components of interest. A measurement is completed within a minute and a variety of nutrients and metabolites can be detected in a single spectrum. Within this approach, PLS-models have been developed to predict the concentration of Glucose, Ethanol, Glycerol, Acetic acid, Ammonium and Phosphate in a yeast fermentation process.The method has been developed on a lab-scale fermentation setup, using YPD medium as a complex nutrient source, adjusting the operating conditions to mimic industrial operation. Our calibration models are built on both several yeast batch-fermentations, representing relevant different process conditions, and synthetic samples serving the need of decoupling the natural correlation dynamics of the target species. Additionally, IR spectra were collected with a classical FTIR instrument and the novel patented upconversion technology NLIR. The NLIR technology is considered for atline application and models built on both spectral datasets were compared regarding their performance.