U. Müller

Secondary Metabolites by Extractive Fermentation

Product yield infermentation processes is often limited by product inhibition or degradation. This may be avoided by extracting the product from the broth during fermentation. Solvents to be used in these extractive fermentations must be selective for the product and non-toxic for the microorganism. For the formation of cycloheximide by Streptomyces griseus and gibberellic acid by Gibberella fujikuroi the procedure of solvent selection is exemplified. It is shown that substituted polyglycols are well suited for the requirements of extractive fermentations of secondary metabolites. Furthermore, process variants for performing an extractive fermentation are presented.

SURFACTANT MEDIATED EXTRACTION OF TRITERPENES AND THEIR DIRECT HPLC ANALYSIS FROM THE MICELLAR SYSTEM

The pentacyclic triterpenes oleanolic acid (OA) and ursolic acid (UA) in Salvia triloba are attractive ingredients for cosmetic and pharmaceutical formulations. These triterpenoids are constitution isomers and differ only in the position of one methyl group in their chemical structures. Therefore it is difficult to achieve a baseline separation by standard RP-HPLC systems. Another challenge is that the complex plant contains a large variety of similar compounds. To achieve precise results for the target molecules, these compounds should be removed prior to analysis. Due to the large application of these two triterpenes, a fast quantification method is favored. If the triterpenes are extracted with aqueous two-phase systems, the target substances are enriched in a surfactant-rich phase. For this application, it is desirable to develop a method that is capable of quantifying both triterpenes directly by RP-HPLC without additional purification steps. The optimal chromatographic conditions for pure substances as well as for crude surfactant-containing extracts were accomplished on a Nucleodur C18 ISIS column by isocratic elution with methanol/water/acetic acid/triethanolamine (90:10:0.04:0.02 v/v) as the mobile phase and a column temperature of 10°C. The flow rate was 0.6 mL/min, and the detection wavelength was 210 nm. With these parameters, a baseline separation was achieved and the calibration curve showed a very good linearity (R2 > 0.999 for OA and UA) within the test range. The method is simple, rapid, and reliable for the quantification of crude extracts from plant material.

Zustandserkennung in Produktionsanlagen durch Asset-Management

Effective management of assets in chemical and pharmaceutical production plant requires a knowledge of their technical, processing, and economic condition. In particular, for plant with high demands on availability it is the task of technical management to assure production capability by ongoing determination of the technical condition, prediction of future wear and tear, and resulting maintenance measures. They thus make an important contribution to the overall value added chain. This review discusses asset management systems offering the technical management of production plant extended sources of information and diagnostic tools for determination of the technical condition of production plant. The article mentions the possibilities and the demands placed on such systems which support both plant-related and control engineering maintenance.