Abstrakti
The application of Raman spectroscopy as a monitoring technique for bioprocesses is severely limited by a large background signal originating from fluorescing compounds in the culture media. Here, we compare time-gated Raman (TG-Raman)-, continuous wave NIR-process Raman (NIR-Raman), and continuous wave micro-Raman (micro-Raman) approaches in combination with surface enhanced Raman spectroscopy (SERS) for their potential to overcome this limit. For that purpose, we monitored metabolite concentrations of Escherichia coli bioreactor cultivations in cell-free supernatant samples. We investigated concentration transients of glucose, acetate, AMP, and cAMP at alternating substrate availability, from deficiency to excess. Raman and SERS signals were compared to off-line metabolite analysis of carbohydrates, carboxylic acids, and nucleotides. Results demonstrate that SERS, in almost all cases, led to a higher number of identifiable signals and better resolved spectra. Spectra derived from the TG-Raman were comparable to those of micro-Raman resulting in well-discernable Raman peaks, which allowed for the identification of a higher number of compounds. In contrast, NIR-Raman provided a superior performance for the quantitative evaluation of analytes, both with and without SERS nanoparticles when using multivariate data analysis.
| Alkuperäiskieli | Englanti |
|---|---|
| Sivut | 1533-1542 |
| Sivumäärä | 10 |
| Julkaisu | Biotechnology Progress |
| Vuosikerta | 34 |
| Numero | 6 |
| DOI - pysyväislinkit | |
| Tila | Julkaistu - 1 marrask. 2018 |
| Julkaistu ulkoisesti | Kyllä |
| OKM-julkaisutyyppi | A1 Julkaistu artikkeli, soviteltu |
Rahoitus
Contract grant sponsor: Biotieteiden ja Ymp€ariston Tutkimuksen Toimikunta; Contract grant number: 1292253 H2020. Contract grant sponsor: SkÅ,odowska-Curie Actions)?>Marie Skłodowska-Curie Actions; Contract grant numbers: 643056; 1292253. Contract grant sponsor: Biotieteiden ja Ymp€ariston Tutkimuksen Toimikunta. Contract grant sponsor: H2020 Marie Skłodowska-Curie Actions. Additional Supporting Information may be found in the online version of this article. Correspondence concerning this article should be addressed to Peter Neubauer at [email protected]. We thank the Academy of Finland, grant agreement no. 1292253 (FOULSENS) and the European Union's Horizon 2020 research and innovation program under the Marie Sk?odowska-Curie actions grant agreement no. 643056 (Biorapid) for financial support. We also thank Dr. Oliver Skibitzki and Dipl. Ing. Brigitte Burckhardt for their support during the measurements. The authors gratefully acknowledge the considerable support of Mari Tenhunen and Lauri Kurki, Timegate Instruments Oy, Oulu, Finland, for temporarily providing a TG-Raman instrument and supporting its qualification. We thank the Academy of Finland, grant agreement no. 1292253 (FOULSENS) and the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie actions grant agreement no. 643056 (Bio-rapid) for financial support. We also thank Dr. Oliver Ski-bitzki and Dipl.-Ing. Brigitte Burckhardt for their support during the measurements. The authors gratefully acknowledge the considerable support of Mari Tenhunen and Lauri Kurki, Timegate Instruments Oy, Oulu, Finland, for temporarily providing a TG-Raman instrument and supporting its qualification.