Beitrag zur quantitativen Bestimmung von Phosphatiden

Contribution towards Quantitative Determination of Phosphatides The author reports about a procedure by which the percentage distribution of individual phosphatides in a lipid extract of natural origin can easily be determined.     

Neue Methoden zur quantitativen Analyse von Etherlipiden

Some New Methods for the Quantitative Analysis of Ether Lipids A simple and reliable procedure for the determination of the ratio alkylglycerolipids to l-alkenylglycerolipids is carried out as follows: A “total lipid extract” is reduced with lithiumaluminiumhydride to yield a mixture of alkylglycerols, l-alkenylglycerols, and alcohols. Acetylation of these reduction products with radioactively labelled acetic anhydride leads to a mixture of alkyldiacetylglycerols, l-alkenyldiacetylglycerols, and alkylacetates. This mixture is resolved into the three lipid classes by thin-layer chromatography on silica gel. The ratios of the radioactive derivatives and, thereby, the ratio ether lipids to ester lipids as well as the ratio alkylglycerolipids to l-alkenylglycerolipids are determined by scanning of the thin-layer chromatograms. For the analysis of the alkyl and l-alkenyl moieties the groups of alkyldiacetylglycerols and l-alkenyldiacetylglycerols are separated from the alkylacetates by thin-layer chromatography and treated with hydrochloric acid in diethylether. The resulting mixture of alkyldiacetylglycerols and aldehydes (derived from l-alkenyldiacetylglycerols) is resolved by gas chromatography. The various aldehydes, which are well resolved from each other, are eluted ahead of the alkyldiacetylglycerols, which are also well resolved from each other. The methods described have been applied to the analysis of the lipids of mammalian hearts and of shark liver oils; they proved to yield precise values in a relatively short time. Methods for the synthesis and analysis of ‘PAF’ (‘Platelet Activating Factor’) are reviewed.     

Einsatz von Prozessberechnungsprogrammen zur Optimierung fortschrittlicher Dampfkraftprozesse

Computational tools are used for the design analysis of power plant cycles. Combination of these with optimisation codes yields efficient optimisation of both cycle topology and cycle parameters. The efficiency of these tools is demonstrated for an advanced steam cycle with double reheating and multiple feed water preheating. For feed water preheating, it is shown that the optimum total amount of preheating, represented by the maximum pressure level of steam extraction, is largely decoupled from the distribution of the individual pressure levels of the succeeding stages of steam extraction.     

Einsatz eines Online-Methanol-Messsystems zur Regelung von Zulaufsatzkultur-Fermentationen

For the optimization of fed-batch fermentations of methylotrophic organisms an online measuring method is presented, with which the methanol concentration in the medium during a fermentation can be determined by a purge gas pervaporation principle. In contrast to other analytical methods, this measuring method offers the possibility of maintaining the substrate concentration at a controlled value in processes with methanol as the central substrate. Difficulties, but also their overcoming in the adaptation of the measuring method to fermentation processes are described.     

Einsatz von Pervaporation-Bioreaktor-Hybridprozessen in der Biotechnologie

Use of Pervaporation/Bioreactor Hybrid Processes in Biotechnology Pervaporation is a membrane separation process with considerable innovative possibilities in the area of biotechnology. Above all, the combination of bioreactor and pervaporation has potential in the longer term as an alternative to conventional batch processes. This article considers the state of the art of pervaporation/bioreactor hybrid processes. The possible applications of such hybrid processes are discussed and compared with conventional processes. It becomes apparent that the use of pervaporation/bioreactor hybrid processes can avoid product inhibition and greatly enhance the productivity of biotechnological processes.