Robert Faurie

Bioanalytics: detailed insight into bioprocesses

The principles of bioanalytical systems for an on-line bioprocess monitoring are described within this paper. These sensor systems can be interfaced to the bioprocess in different ways according to the needs of the single bioprocess. Modular systems are necessary, which can fit exactly to the needs of the single process. Invasive as well as non-invasive bioanalytical tools are described and discussed in detail. Immunosensors give the possibility to monitor high molecular weight components within short time intervals. Non-invasive optical sensors allow the direct monitoring of various analytes such as oxygen pH for the complex fluorescence behavior of the bioprocess medium. These so-called fluorescence sensors offer the possibility to monitor intra- as well as extracellular components without interfering with the bioprocess. An industrial example for the application of bioanalytical tools for a process optimization are presented in this application. Here a biosensor system is used to optimize the downstreaming of molasses on a technical scale. The economic as well ecological advantages are discussed.

Monitoring and control of industrial downstream processing of sugar beet molasses.

In present work the determination of several amino acids during the industrial chromatographic desugarisation of molasses is presented. The use of innovative biosensor systems for highly specific detection of serine is described. Using two-dimensional fluorescence spectrometry, a non-invasive method for the determination of several product fractions could be established in an industrial chromatographic procedure.

Modelling of an Industrial Biotransformation Process for Tryptophan Production

Abstract For an industrial biotransformation process a simple mathematical model has been developed. During the process indole and serine is converted to tryptophan using the enzyme tryptophan synthase, which is supplied in E. coli cells. The tryptophan production has been described by a first order kinetic with respect to serine and the relative cell concentration as well as zero order kinetics with respect to indole. The 10.000 L reactor, in which the production is performed, is described as an ideal stirred tank reactor. The activity of the cell suspension, i. e. the activity of the tryptophan synthase, which was considered in one of the model parameter could be determined from fluorescence measurements (fluorescence intensity at 350 run excitation and 470 nm emission wavelength) using a linear regression model. The model prediction corresponds very well with off-line measurement

Two-dimensional fluorescence spectroscopy for online monitoring of chromatographic separation of molasses

Monitoring and control of industrial or biotechnological processes invariably require reliable and fast analytical systems. Two-dimensional spectral fluorescence allows real time automatic measurements directly inside the process and provides a continuous stream of information compared to discrete information available from repeated sampling and offline analysis. Normally, chromatographic molasses desugarization processes are typically monitored with a combination of an online-refractometer, polarimeter and the measurement of density and conductivity. Additional information of the separation profile could be obtained by multiple sampling during the separation cycle followed by offline laboratory analysis. An optical sensor (BioViewR) allows online fluorescence measurements for a continuous monitoring directly at the outlet of the separation columns. It was the aim to predict the amino acid serine during the chromatographic cycle. Based on fluorescence, it was possible to monitor a fluorophor, which eluted a few minutes before the serine fraction during molasses desugarization. The application of fluorescence measurements for monitoring and control of chromatographic separation process may improve yield and purity of the separating fractions and can lower the costs for the next downstream processing of by-products.