Karl Schügerl

The use of molds in pellet form

Abstract The cost of providing power to disperse gas and mix the contents of fermenters contributes significantly to overall process economics. The major factor affecting the power demand is the viscosity of the fermentation medium, and this can be substantially reduced by growing molds in the form of pellets rather than as filaments. Studies on Penicillium chrysogenum demonstrate the advantages of inoculating fermentation media with pelleted molds.

Challenges in integrating biosensors and FIA for on-line monitoring and control

Several obstacles prevent the increased use of biosensors in industrial bioprocess monitoring and control. Among these are the absence of robust and reliable biosensors with the required specificity and sensitivity for use in complex media, and the absence of adequate sampling techniques. Progress with the integration of amperometric and potentiometric biosensors into flow injection analysis (FIA) systems may provide a route to developing automated, reliable, on-line systems for bioprocess control.

Interfacial activity of some model extractants containing sulphur

Abstract Interfacial tension isotherms were determined in octane/water and toluene/water systems for some model palladium (II) extractants and accelerators containing sulphur and nitrogen atoms. The effects of compound structures and their polarity upon their interfacial tension and surface excess isotherms were discussed.

Interfacial activity of lactic acid extractants containing oligo-oxyethylene fragments

Abstract The equilibrium interfacial tension isotherms of amine extractants containing oligo-oxyethylene fragments were determined for model extraction systems containing lactic acid. The influence of compound structure upon the interfacial effectiveness and efficiency was discussed. The high interfacial activity of the α,ω-diamino-oligoethers C 12 H25 NHCH 2 (CH 2 OCH 2 ) 2 CH 2 NHC 12 H 25 and C 8 H 17 (PhCO)NCH 2 (CH 2 OCH 2 ) 4 CH 2 N(OCPh)C 8 H 17 was demonstrated and these compounds were screened as potential lactic acid extractants.

Crown Ethers in Separation of Alkali Metal Cations1

Strzelbicki, J., Strzelbicka, B., Schugerl, K. and Bartsch, R. A., 1990. Crown ethers in separation of alkali metal cations. Proceedings of the International Solvent Extraction Conference 1990, Kyoto, Japan, July 16 - 21, 1990. Results are presented on separation of alkali metal cations (AMC) using a protonionizable and a neutral crown ether. sym-(Decyl)dibenzo-16-crown-5-oxyacetic acid was used as a selective ion-carrier in separation of Na+ from a mixture of Li+, Na+, K+ and Rb+ by means of hollow fiber supported liquid membranes. Selectivity of the permeation was very high. No Rb+ was transported in the system and Na/Li and Na/K selectivity coefficients reached 80 and 42, respectively. Expensive and/or commercially unavailable compounds involved and complicated operation were disadvantages of this process. In separation of AMC by liquid-liquid extraction, mixtures of dicyclohexano-18-crown-6 with di(2-ethylhexyl)phosphoric acid or with di(2-ethylhexyl)monothiophosphoric acid were used for complexation of AMC and their transfer into an organic phase. Selectivity of one stage liquid-liquid extraction was lower compared to liquid supported membrane process. On the other hand, reagents used in solvent extraction are commercially available, relatively inexpensive and the process is simple to perform.

Separation of Rhenium and Molybdenum by Liquid Surfactant Membranes

ABSTRACT Strzelbicki, J., Degener, W. and SchuUgerl, K., 1990. Separation of rhenium and molybdenum by liquid surfactant membranes. Proceedings of the International Solvent Extraction Conference 1990, Kyoto, Japan, July 16 - 21, 1990. Separation of Re from solutions containing a high excess of Mo by liquid surfactant membranes using diisotridecylacetamide, diisotridecylamine, tri(n-octyl/n-decyl)amine and tri(n-octyl/n-decyl)methylammonium chloride is described. Diisotridecylacetamide was found as the most selective ion-carrier which transported more than 99 % of Re from the feed solution into the receiving solution and only inconspicuous amounts of Mo were found in the receiving solution. Influence of various process parameters (ion-carrier concentration, composition of the feed and receiving solution, stability of emulsion) is presented and discussed.