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

Leitermann F, Syldatk C, Hausmann R - J Biol Eng (2008)

Bottom Line: Even better accuracies between 0.28 g/l - 0.59 g/l were found for independent test samples of an arbitrarily selected cultivation.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.

View Article: PubMed Central - HTML - PubMed

Affiliation: Research University Karlsruhe, Institute of Engineering in Life Sciences, Section of Technical Biology, Engler-Bunte-Ring 1, 76131 Karlsruhe, Germany. Rudolf.Hausmann@tebi.uni-karlsruhe.de.

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.

No MeSH data available.


Rhamnolipid 3 IR-spectrum. ATR-FTIR spectrum of an aqueous solution (89 mg/mL) of rhamnolipid 3. The allocation of conspicuous absorption to corresponding characteristic group absorptions from literature was attempted.
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Figure 1: Rhamnolipid 3 IR-spectrum. ATR-FTIR spectrum of an aqueous solution (89 mg/mL) of rhamnolipid 3. The allocation of conspicuous absorption to corresponding characteristic group absorptions from literature was attempted.

Mentions: An ATR-FTIR spectrum of pure rhamnolipid 3 in water was recorded, as shown in Figure 1. For a better understanding of the IR spectrum, subsequently the dominant absorbance bands were correlated to the according group absorbance frequencies. The broad negative bands at about 3300 cm-1 and 1640 cm-1 result from a higher water concentration in the reference spectrum (pure water) relative to the aqueous sample, and are attributed to hydrogen bonding and O-H stretching of water. The double bands at 2921 and 2855 cm-1 are derived from symmetric C-H stretching vibrations of aliphatic groups, like those represented in the hydroxydecanoic acid chain tails of rhamnolipid 3. A C=O stretching band at 1730 cm-1 is characteristic of ester bonds and carboxylic acid groups. In the fingerprint region of the spectrum, the area between 1200 – 1460 cm-1 represents C-H and O-H deformation vibrations, typical for carbohydrates as in the rhamnose units of the molecule, for example. The lower range of the fingerprint region below 1200 cm-1 represents different kinds of C-H, C-O and CH3 vibrations which cannot be allocated more closely [6].


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

Leitermann F, Syldatk C, Hausmann R - J Biol Eng (2008)

Rhamnolipid 3 IR-spectrum. ATR-FTIR spectrum of an aqueous solution (89 mg/mL) of rhamnolipid 3. The allocation of conspicuous absorption to corresponding characteristic group absorptions from literature was attempted.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2572035&req=5

Figure 1: Rhamnolipid 3 IR-spectrum. ATR-FTIR spectrum of an aqueous solution (89 mg/mL) of rhamnolipid 3. The allocation of conspicuous absorption to corresponding characteristic group absorptions from literature was attempted.
Mentions: An ATR-FTIR spectrum of pure rhamnolipid 3 in water was recorded, as shown in Figure 1. For a better understanding of the IR spectrum, subsequently the dominant absorbance bands were correlated to the according group absorbance frequencies. The broad negative bands at about 3300 cm-1 and 1640 cm-1 result from a higher water concentration in the reference spectrum (pure water) relative to the aqueous sample, and are attributed to hydrogen bonding and O-H stretching of water. The double bands at 2921 and 2855 cm-1 are derived from symmetric C-H stretching vibrations of aliphatic groups, like those represented in the hydroxydecanoic acid chain tails of rhamnolipid 3. A C=O stretching band at 1730 cm-1 is characteristic of ester bonds and carboxylic acid groups. In the fingerprint region of the spectrum, the area between 1200 – 1460 cm-1 represents C-H and O-H deformation vibrations, typical for carbohydrates as in the rhamnose units of the molecule, for example. The lower range of the fingerprint region below 1200 cm-1 represents different kinds of C-H, C-O and CH3 vibrations which cannot be allocated more closely [6].

Bottom Line: Even better accuracies between 0.28 g/l - 0.59 g/l were found for independent test samples of an arbitrarily selected cultivation.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.

View Article: PubMed Central - HTML - PubMed

Affiliation: Research University Karlsruhe, Institute of Engineering in Life Sciences, Section of Technical Biology, Engler-Bunte-Ring 1, 76131 Karlsruhe, Germany. Rudolf.Hausmann@tebi.uni-karlsruhe.de.

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.

No MeSH data available.