Methodology

Fast quantitative determination of microbial rhamnolipids from cultivation broths by ATR-FTIR Spectroscopy

Frank Leitermann , Christoph Syldatk and Rudolf Hausmann

Research University Karlsruhe, Institute of Engineering in Life Sciences, Section of Technical Biology, Engler-Bunte-Ring 1, 76131 Karlsruhe, Germany

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Journal of Biological Engineering 2008, 2:13doi:10.1186/1754-1611-2-13

Published:	7 October 2008

Abstract

Background

Vibrational spectroscopic techniques are becoming increasingly important and popular because they have the potential to provide rapid and convenient solutions to routine analytical problems. Using these techniques, a variety of substances can be characterized, identified and also quantified rapidly.

Results

The rapid ATR-FTIR (Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy) in time technique has been applied, which is suitable to quantify the concentrations of microbial rhamnolipids in a typical cultivation process. While the usually applied HPLC analysis requires an extensive and time consuming multi step extraction protocol for sample preparation, the ATR-FTIR-method allows the quantification of the rhamnolipids within 20 minutes. Accuracies between 0.5 g/l – 2.1 g/l for the different analytes were determined by cross validation of the calibration set. Even better accuracies between 0.28 g/l – 0.59 g/l were found for independent test samples of an arbitrarily selected cultivation.

Conclusion

ATR-FTIR was found to be suitable for the rapid analysis of rhamnolipids in a biotechnological process with good reproducibility in sample determination and sufficient accuracy. An improvement in accuracy through continuous expansion and validation of the reference spectra set seems very likely.