Conditions were developed for the reproducible production, isolation and characterization of a novel microbial extracellular polysaccharide believed to be involved in transient viscous bulking at an industrial wastewater treatment plant. The exopolysaccharide was extracted from cell-free culture supernatants of Thauera sp. strain MZ1T grown on a minimal medium with succinate. The purified polymer was found to be approximately 260 kDa in size by gel-permeation chromatography. The GC-MS analysis of the alditol acetate and per-O-trimethylsilyl methyl glycoside derivatives revealed that the exopolysaccharide was composed of four monosaccharides including: rhamnose, galacturonic acid, N-acetylglucosamine and N-acetylfucosamine. Glucose, which also appeared at low levels, is most likely from a co-eluting glucan. The FTIR and NMR spectroscopic analyses further revealed the presence of esterified component groups on the polymer. These results represent the first published description of a polysaccharide from a member of the genus Thauera, and lay the foundation for a deeper understanding of the factors potentially involved in zoogloeal cluster formation and viscous bulking.

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Dendrimers are modified polymers whose architecture is defined by the presence of a central atom or core with multiple branches. These molecules lend themselves to a variety of architectures and uses, including drug delivery and catalysis. The study of the molecular conformations and shapes of dendritic molecules is necessary but not yet routine. Here we present an NMR and molecular modeling study of a series of carbosilane dendrimers, namely 1G-{(CH2)3[C6H3(OMe)]OH}4 (1), 2G-{(CH2)3[C6H3(OMe)]OH}8 (2), and 2G-{(CH2)3[C6H3(OMe)]O[Ti(C5H5)Cl2]}8 (3). Various two-dimensional NMR techniques were used to completely assign the 1H and 13C resonances of molecules 1-3. This information was used, in conjunction with 1H and 13C spin-lattice relaxation measurements, to assess the chain motion of the molecules. The NMR data were also compared with 1-ns molecular dynamics (MD) simulations of 1 and 2 using the MMFF94 force field. The results indicate that these dendrimers possess a core that is motionally decoupled from the rest of the dendrimer, with flexible arm segments that extend from the core. The addition of eight functionalized titanium groups to the ends of the dendrimer chains of 2 to yield molecule 3 serves to further restrict chain motion.

Quenched molecular dynamics (QMD), in conjunction with NMR (ROESY) studies, was used to investigate the conformational behavior of some semibiosynthetic anthocyanins of the type 6-O-acyl-beta-D-Glcp-(166)-beta-D-Galp-(1-->O(3))-cyanidin, with and without a beta-D-Xylp branch at the 2-O-Gal position. These compounds, which are produced by the addition of selected carboxylic acids to growing tissue cultures of Daucus carota (wild carrot), are of interest as color-stabilized anthocyanins, some of which have potential as useful colorants in the nutraceutical and pharmaceutical industries. The QMD-ROESY studies, performed for the first time on anthocyanins, have led to the identification of families of conformers of these flexible molecules that are of interest in work toward determining the mechanism for stabilization of color among these compounds in solution.