The residual buildup and treatment of dissolved contaminants in low permeable zones (LPZs) is a particularly challenging issue for injection-based remedial treatments. Our objective was to improve the sweeping efficiency of permanganate into LPZs to treat dissolved-phase TCE. This was accomplished by conducting transport experiments that quantified the ability of xanthan-MnO4(-) solutions to pe...

When grown on xanthan as a carbon source, the bacterium Bacillus sp. strain GL1 produces extracellular xanthan lyase (75 kDa), catalyzing the first step of xanthan depolymerization (H. Nankai, W. Hashimoto, H. Miki, S. Kawai, and K. Murata, Appl. Environ. Microbiol. 65:2520-2526, 1999). A gene for the lyase was cloned, and its nucleotide sequence was determined. The gene contained an open readi...

Xanthan biopolymer has been produced by single-stage continuous ferment~ tion with Xanthomonas campestris NRRL B-1459 in a medium of glucose, minerals, distillers' solubles, and urea for as long as 20 days. At the highest dilution rate studied (D = 0.0285 hr-1), the steady state rate of xanthan production was 0.36 g/kg/hr and ·the steady state yield, basis glucose consumed, was 68%. Observation...

Xanthan gum is an anionic heteropolysaccharide produced by the bacterium Xanthomonas campestris. Synergistic galactomannan – xanthan gum interactions are used for commercial and technological applications. Prosopis seed gum were mixed with xanthan gum (Sigma, U.S.A) at the following ratios 100/0, 80/20, 60/40, 40/60, 20/80, 0/100 (0.5 % ). Solutions (w/w) were prepared and heated for 1 h. After...

The hierarchical morphology of xanthan solutions is analyzed by light and neutron scattering in a broad range of concentrations in order to connect their morphology to their well-documented dynamic properties. Static light scattering inside the semidilute regime is dominated by the form factor of individual xanthan chains while at higher concentrations chain interconnections appear to modify th...

Cassava starch is a main renewable bio-resource with low price and mass production in Guangxi, China. It was used as carbon source in growing Xanthomonas campestris pv. campestris 8004 (Xcc 8004) for xanthan gum production in this study. The xanthan gum yield of gelatinized cassava starch was higher than that of raw cassava starch; the maximal reducing sugar and amylase activity reached 14.30 g...

background and objective : the genus xanthomonas is composed of phytopathogenic bacterial species. in addition to causing crops diseases, most of the xanthomonas species especially xanthomonas campestris produce xanthan gum via an aerobic fermentation process. xanthan gum is, an important exopolysaccharide from xanthomonas campestris, mainly used in the food, petroleum and other industries. the...

Background: A number of microorganisms and their enzymes have been reported as xanthan depolymerizers. Paenibacillus species are well-known polysaccharide hydrolyzing bacteria. However, Paenibacillus alginolyticus and Paenibacillus sp. XD are the only species in the genus which are now known to degrade xanthan. Objectives: Complete biodegradation of the xanthan exopolysaccharide is a rarely fou...

The synergistic interaction between xanthan and glucomannan in solution and in the gel phase has been studied by circular dichroism spectroscopy and differential scanning calorimetry. The study in solution of the polysaccharidic mixture indicates a preferred stoichiometry of the interaction corresponding to a weight fraction of xanthan around 0.55. This finding is in reasonable agreement with t...