Mikrobielle und enzymatische Synthese von Biotensiden auf der Basis nachwachsender Rohstoffe

Microbial and Enzymatic Synthesis of Biosurfactants from Renewable Resources Renewable resources such as vegetable oils or carbohydrates are suitable substrates for the biocatalysis to produce glycolipids with good physico-chemical properties and biological activities. Potential biotechnological processes include: Multiple-step-biosynthesis by microorganisms (growth-limited cultures, resting cells) and one-step-reaction with lipases or glycosidases. By aid of the microbial method the specific production amounts to more than 50 % conversion of the renewable resources to high value glycolipids. A disadvantage is the limited variability of the molecular structures. The enzymatic method offers the directed synthesis of glycolipids from sugar and fatty acid/fatty alcohol, but needs partly those additional procedures which are necessary in competing chemical methods.     

Olechemie – Chemieprodukte auf der Basis nachwachsender Rohstoffe

Oleochemistry – Chemical Products Based On Renewable Raw Materials . Because of the increasing demand of consumers and industry for “green” products, the importance of the oleochemistry will grow in the future. This paper shows that the modern oleochemistry has developed from ?soapboiling”? to a part of the chemical industry which requires all elements of chemical engineering. A wide and pretentious area of activities concerning unit operations and reaction technology is offered to the chemical engineer. The thermal sensitivity of raw materials and products results in high demands in the production process.     

MALDI-TOF-MS: Eine neue analytische Technik zur Charakterisierung von Produkten auf Basis nachwachsender Rohstoffe

MALDI-TOF-MS: A new analytical technique for characterizing products on the base of renewable resources. For the ionization of non-volatile highly polar or high-mass substances a new mass spectrometric technique, the Matrix Assisted Laser Desorption and Ionization Time of Flight Mass Spectrometry (MALDI-TOF-MS) has been established which is very suitable for the analysis of oligomeric or polymeric substances synthesized on the base of renewable materials. In the following article the new method is introduced and its performance is demonstrated by examples of surfactants and emulsifiers.     

Polyole auf Basis fettchemischer Rohstoffe

Polyols on the Basis of Oleochemical Raw Materials Ether alcohols (polyols), which are of interest in a number of fields of application such as, e. g., PU foams, PU dispersions and PU casting resins, are readily accessible by the acid-catalyzed conversion of epoxidized fatty materials with mono- and polyvalent alcohols. By means of epoxidized triglycerides and epoxidized oleyl alcohol it is exemplified how polyols with a wideley variable hydroxyl value can be built up by variation of the reaction course or the alcohol component. Two selected fields of application are illustrated in more detail.     

Biologischer Abbau chlorierter Kohlenwasserstoffe

Biological Degradation of Chlorinated Hydrocarbons . Chlorinated hydrocarbons (CHC) have been produced on an industrial scale since the 1920's and 1930's and are frequently used as solvents, extractants, and disinfectants. Because their low biodegradability they are often enriched in the food chains of animals, resulting in high mortality. It is therefore necessary to prevent the discharge of CHC's into water, air, and soil. They are often not biodegraded in municipal or industrial activated sludge plants or in trickling filters. Until harmless substitutes become widely available, CHC's will continue to pose a threat and must be eliminated from all effluents before entering wastewater treatment plants. Information about specific conditions for anaerobic and aerobic biodegradation of selected CHC's is given below. Two topics will be discussed in greater detail: the kinetics of dechlorination and mineralization and some examples of the reaction engineering process in lab and pilot scale.     

Mikrobielle Sensoren auf Basis von Respirationsmessungen

Microbial sensors based on respiration measurements. Microbial sensors based on the direct contact of microbe and a transducer convert the chemical composition of the sample into a quantitative electrical signal. They are useful for the determination of a wide range of substrates but also of “group effects” for bioprocess control and environmental protection. Starting from the physiological fundamentals – including various ways of influencing sensor performance - this paper reviews the present state of the development of microbial sensors. Different sensor types developed by the authors's group are presented.     

Modellierung der Methanolsynthese auf Basis von Elementarreaktionen

Using the transition state theory, parameters like the pre‐exponential factor and activation energy can be related to the active centers. These parameters suggest how a technical process can be described, even if the predominating geometries between the adsorbed species and the substrate are not known exactly. The approach to modelling methanol synthesis presented here shows that elementary reactions can be combined with simple coupled differential equations to derive major conclusions with respect to surface reactions of the catalyst.     

Ozoninduzierter Abbau von Polyoxymethylen

Samples of polyoxymethylene (unstabilized and stabilized with the antiozonants N-isopropyl-N′-phenyl-p-phenylenediamin (IPPD) and bis-(1,2,3,6-tetrahydrobenzaldehyd)pentaerithritylacetal (Vulkazon AFS)) were ozonized under mechanical load in a special climate chamber. Surface damages were determined by IR-spectroscopy and scanning electron microscopy. During the ozonolysis a damaged layer is formed, the thickness of which increases with increasing time of ozonization. During this damaging reaction acetal groups are attacked and oligomers are formed.     

Zum biologischen Abbau von Dibenzofuran im Hinblick auf dioxinähnliche Verbindungen

A Contribution to the Biological Degradation of Dibenzofurane with Regard to Dioxins A bacteria was isolated by submerse culturing which is growing on dibenzofurane as the sole carbon source. The adaptation was performed on an activated carbon fixedbed reactor in connection with dibenzofurane and dioxins containing drain water of a disposal for waste chemicals. As a first step of metabolism diphenylether was recognised. This indicates why the furanes within the dioxin-family in the environment are not found in the same concentration as the dioxins although both are emitted most in nearly the same ratio. An other particular feature of the bacteria is the forming of saturated hydrocarbons. The number of carbonatoms goes from 20 to 32, as well even as uneven and as well by aerobic as unaerobic culturing.     

Hochselektive pH-Festkontakt-Sensoren auf der Basis von Protonen-Carrier-PVC-Membranen mit polymeren Weichmachern

Highly Selective pH-Solid-State-Sensors Based on Proton-Carrier-PVC-Membranes with Polymeric Plasticizers Basing on membrane chemical experiments, the systematic development of a highly selective proton carrier PVC membrance for solid state contact sensors with trioctylamine as ligand and a phthalic acid polyester as polymeric plasticizer is described. Its resistance to saponification leads, compared to monomeric plasticizers, to higher stability of measured values of alkaline solutions. The incorporation of lipophilic anions is indispensable for the repulsion of elements of negative charge. The membrane systems' selectivity is strongly influenced by the ligand's exolipophilic periphery. Several membrane systems attractive for analysis are specified.