Yeastolate or yeast extract which are hydrolysates produced by autolysis of yeast, are often employed as a raw material in the media used for industrial mammalian cell culture. The source and quality of yeastolate can significantly affect... more
Yeastolate or yeast extract which are hydrolysates produced by autolysis of yeast, are often employed as a raw material in the media used for industrial mammalian cell culture. The source and quality of yeastolate can significantly affect cell growth and production, however, analysis of these complex biologically-derived materials is not straightforward. The best current method, liquid chromatography-mass spectrometry (LC-MS) is time-consuming and requires extensive expertise. This study describes the use of surface-enhanced Raman scattering (SERS) and fluorescence excitation-emission matrix (EEM) spectroscopy coupled with robust principal component analysis (ROBPCA) for the rapid and facile characterization and discrimination of yeast extracts in aqueous solution. SERS using silver colloids generates time-dependant signals where adenine is the strongest contributor, and the spectra are stable and reproducible (< ~3%) at 180 minutes after mixing. Combining this spectral behavior with chemometric methods enables SERS to be used for discriminating between different yeastolate sources, for assessing lot-to-lot variability, and potentially to monitor storage-induced compositional changes. Fluorescence EEM combined with multiway ROBPCA also provides a rapid and inexpensive method for discrimination of yeastolate, yielding very similar results in terms of sample discrimination to that obtained by SERS. However, the EEM data does not provide the same level of chemical information as provided by the SERS. Thus the combination of the two methodologies has the potential to be extremely useful in biopharmaceutical manufacturing for the rapid characterization and screening of biogenic hydrolysates from animal or plant sources.
