In situ bioprocess monitoring of Escherichia coli bioreactions using Raman spectroscopy

We have demonstrated simultaneous concentration estimation of glucose, acetate, formate, lactate, and phenylalanine from in situ measured Raman spectra in Escherichia coli bioreactions. Attenuation due to light scattering from air bubbles and biomass was corrected by internally referencing the least-squares estimated concentrations to the estimated water concentration. Estimation accuracy was limited by errors in the physical model for the system, rather than noise. Eliminating model errors should enable shot-noise limited detection in the 0.1 mM range. (C) 2003 Published by Elsevier B.V.