Institution
DECHEMA
Nonprofit•Frankfurt am Main, Germany•
About: DECHEMA is a nonprofit organization based out in Frankfurt am Main, Germany. It is known for research contribution in the topics: Corrosion & Oxide. The organization has 756 authors who have published 1307 publications receiving 25693 citations.
Papers published on a yearly basis
Papers
More filters
••
TL;DR: The whole cell catalyst containing LOX and HPL enzyme activity described here can be a promising approach towards a highly efficient microbial green note synthesis process.
Abstract: Green notes are substances that characterize the aroma of freshly cut grass, cucumbers, green apples, and foliage. In plants, they are synthesized by conversion of linolenic or linoleic acid via the enzymes lipoxygenase (LOX) and hydroperoxide lyase (HPL) to short-chained aldehydes. Current processes for production of natural green notes rely on plant homogenates as enzyme sources but are limited by low enzyme concentration and low specificity. In an alternative approach, soybean LOX2 and watermelon HPL were overexpressed in Saccharomyces cerevisiae. After optimization of the expression constructs, a yeast strain coexpressing LOX and HPL was applied in whole cell biotransformation experiments. Whereas addition of linolenic acid to growing cultures of this strain yielded no products, we were able to identify high green note concentrations when resting cells were used. The primary biotransformation product was 3(Z)-hexenal, a small amount of which isomerized to 2(E)-hexenal. Furthermore, both aldehydes were reduced to the corresponding green note alcohols by endogenous yeast alcohol dehydrogenase to some extent. As the cosolvent ethanol was the source of reducing equivalents for green note alcohol formation, the hexenal/hexenol ratio could be influenced by the use of alternative cosolvents. Further investigations to identify the underlying mechanism of the rather low biocatalyst stability revealed a high toxicity of linolenic acid to yeast cells. The whole cell catalyst containing LOX and HPL enzyme activity described here can be a promising approach towards a highly efficient microbial green note synthesis process.
48 citations
••
TL;DR: In this paper, the authors tried to confirm the results of the recent paper by Fleischmann and Pons in this Journal by adding additional check experiments and discussed some possible sources of error which should be eliminated carefully in future experiments.
48 citations
••
TL;DR: A one-pot multi-step approach comprising enzymatic oxidation-hydroxymethylation-reduction enables the synthesis of optically active α-aryl vicinal diols with high yields and enantioselectivities.
48 citations
••
TL;DR: There are a number of mechanisms of the conjoint action of flow and corrosion that result in four types of flow-induced corrosion: mass transport controlled corrosion, phase transport controlled, erosion corrosion, and cavitation corrosion as mentioned in this paper.
48 citations
••
TL;DR: In this article, the authors deal with the stresses generated during high temperature oxidation and their relationship to scale fracture and show that growth stresses in the oxide films are negligible compared to thermal stresses, probably due to stress relaxation at high temperature.
Abstract: This paper deals with the stresses generated during high temperature oxidation and their relationship to scale fracture. In the first part, the objective is to differentiate growth stresses from thermal stresses and give evidence for relaxation phenomena. The results obtained for materials which develop NiO, Cr2O3 or Al2O3 scales indicate that, in most cases, growth stresses in the oxide films are negligible compared to thermal stresses, probably on account of stress relaxation at high temperature. Moreover, the stress sign in the oxide scale is inconsistent with conventional views based on the Pilling-Bedworth ratio, but closely related to the growth mechanism of the oxide: a preponderantly cationic diffusion leads to tensile stresses, whereas a preponderantly anionic diffusion leads to compressive stresses. Thermal stresses are closely related to the differences between the expansion coefficients of the scale and the substrate, but can be modified by parameters which can promote stress relaxation such a...
47 citations
Authors
Showing all 760 results
Name | H-index | Papers | Citations |
---|---|---|---|
Wolf B. Frommer | 105 | 345 | 30918 |
Michael W. Anderson | 101 | 808 | 63603 |
João Rocha | 93 | 1521 | 49472 |
Martin Muhler | 77 | 606 | 25850 |
Michael Hunger | 60 | 295 | 11370 |
Ivars Neretnieks | 44 | 224 | 7159 |
Michael Schütze | 40 | 343 | 6311 |
Jens Schrader | 38 | 129 | 4239 |
Roland Dittmeyer | 31 | 206 | 3762 |
Lei Li | 29 | 198 | 4003 |
Dirk Holtmann | 29 | 107 | 3033 |
Lasse Greiner | 26 | 74 | 1994 |
Klaus-Michael Mangold | 23 | 57 | 1590 |
A. Rahmel | 23 | 59 | 1967 |
Gerhard Kreysa | 22 | 78 | 1305 |