The dipotassium salts of maleic, fumaric and acetylenedicarboxylic acids were electrooxidized and the reaction products were analyzed qualitatively and quantitatively by UV/VIS and FT-IR spectroscopy. Acetylene, carbon dioxide and carbon monoxide, along with polyynes, are the products obtained from maleic and fumaric acids. The best acetylene yields are obtained from fumaric acid and not from m...

It is doubtful that the glyoxylate bypass plays a significant role in the accumulation of fumaric acid by fungi, as has been postulated. In high glucose media, which favor fumarate production, isocitrate lyase (threo-D(s) isocitrate glyoxylate lyase), which is the key enzyme of the glyoxylate bypass, is strongly repressed. The specific activity of this enzyme remains low as long as glucose is p...

An enhanced, xylose-utilizing strain of Rhizopus arrhizus was successfully developed via modification using media with increasing concentrations of xylose. Xylose, a relatively cheap monosugar that can be easily obtained from corncobs, rice straw, and vinasse, was the sole carbon source used for both the seed culture phase and the fermentation process. After modification, this newly improved st...

No one of the methods proposed for the synthesis of aspartic acid is entirely satisfactory as a practical procedure. The synthesis, described in a recent paper (1) from this laboratory, has been utilized in preparing 50 to 60 gm. lots of recrystallized aspartic acid but even here the beginning reagents are expensive, the over-all yield is only about 30 per cent of the theoretical, and the proce...

An ion chromatographic method was developed which is able to separate five unsubstituted and hydroxy C4 dicarboxylic acids, succinic, malic, tartaric, maleic and fumaric acid, besides the other unsubstituted C2-C5 dicarboxylic acids, oxalic, malonic and glutaric acids, as well as inorganic ions in samples extracted from atmospheric particulate matter. By the application of this method it was fo...

Background: Non-invasive tumor characterization and monitoring are among the key goals of medical imaging. Using hyperpolarized 13C-labelled metabolic probes fast metabolic pathways can be probed in real-time, providing new opportunities for tumor characterization. In this in vitro study, we investigated whether measurement of apparent diffusion coefficient (ADC) measurements and magnetic reson...

In the title compound, C11H12N2O2·C4H4O4·H2O, the l-tryp-to-phan mol-ecule crystallized as a zwitterion, together with a neutral fumaric acid mol-ecule and a water solvent mol-ecule. In the crystal, the three components are linked by a series of N-H⋯O, O-H⋯O and C-H⋯O hydrogen bonds, forming slabs lying parallel to (001). The slabs are connected by O-H⋯O hydrogen bonds, involving inversion-rela...