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On-line monitoring of recombinant bacterial cultures using multi-wavelength fluorescence spectroscopy

Paper ID Volume ID Publish Year Pages File Format Full-Text
3694 182 2011 7 PDF Available
Title
On-line monitoring of recombinant bacterial cultures using multi-wavelength fluorescence spectroscopy
Abstract

Multi-wavelength fluorescence spectroscopy was evaluated as a tool for on-line monitoring of recombinant Escherichia coli cultivations expressing human basic fibroblast growth factor (hFGF-2). The data sets for the various combinations of the excitation and emission spectra from batch cultivations were analyzed using principal component analysis. Chemometric models (the partial least squares method) were developed for correlating the fluorescence data and the experimentally measured variables such as the biomass and glucose concentrations as well as the carbon dioxide production rate. Excellent correlations were obtained for these variables for the calibration cultivations. The predictability of these models was further tested in batch and fed-batch cultivations. The batch cultivations were well predicted by the PLS models for biomass, glucose concentrations and carbon dioxide production rate (RMSEPs were respectively 5%, 7%, 9%). However, when tested for biomass concentrations in fed-batch cultivations (with final biomass three times higher than the highest calibration data) the models had good predictability at high growth rates (RMSEPs were 3% and 4%, respectively for uninduced and induced fed-batch cultivations), which was as good as for the batch cultivations used for developing the models (RMSEPs were 3% and 5%, respectively for uninduced and induced batch cultivations). The fed-batch cultivations performed at low growth rates exhibited much higher fluorescence for fluorophores such as flavin and NAD(P)H as compared to fed-batch cultivations at high growth rate. Therefore, the PLS models tended to over-predict the biomass concentrations at low growth rates. Obviously the cells changed their concentration of biogenic fluorophores depending on the growth rate. Although multi-wavelength fluorescence spectroscopy is a valuable tool for on-line monitoring of bioprocess, care must be taken to re-calibrate the PLS models at different growth rates to improve the accuracy of predictions.

► We present results from the production of recombinant hFGF-2 by Escherichia coli. ► PLS models are presented to estimate biomass, glucose and CPR. ► Extrapolation of PLS models possible. ► Changes in the fluorescence spectra are presented depending on growth rate. ► Growth rate influences concentration of flavin-like molecules and NAD(P)H.

Keywords
Fluorescence spectroscopy; On-line monitoring; Escherichia coli; Cultivation; Chemometrics; Human basic fibroblast growth factor
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Publisher
Database: Elsevier - ScienceDirect
Journal: Biochemical Engineering Journal - Volumes 58–59, 15 December 2011, Pages 133–139
Authors
, , , , ,
Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us