A novel xanthan depolymerase (endo -1,4-glucanase) was isolated from a salt-tolerant bacteria culture (HD1) grown on xanthan. The depolymerase was purified 55-fold through chromatography on ion-exchange and molecular sieve columns, including high-performance liquid chromatography. The purified enzyme fraction was homogeneous as judged by polyacrylamide gel electrophoresis. The molecular weight ...

Xanthan gum, a complex polysaccharide comprising glucose, mannose and glucuronic acid residues, is involved in numerous biotechnological applications in cosmetics, agriculture, pharmaceuticals, food and petroleum industries. Additionally, its oligosaccharides were shown to possess antimicrobial, antioxidant, and few other properties. Yet, despite its extensive usage, little is known about xanth...

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 p...

Diatom biofilms are abundant in the marine environment. It is assumed (but untested) that extracellular polymeric substances (EPS), produced by diatoms, enable cells to cope with fluctuating salinity. To determine the protective role of EPS, Cylindrotheca closterium was grown in xanthan gum at salinities of 35, 50, 70 and 90 ppt. A xanthan matrix significantly increased cell viability (determin...

Peptide-protein conjugates are useful tools in different fields of research as, for instance, the development of vaccines and drugs or for studying biological mechanisms, to cite only few applications. N-Succinimidyl carbamate (NSC) chemistry has been scarcely used in this area. We show that unprotected peptides, featuring one lysine residue within their sequences, can be converted in good yiel...

The conformation and flexibility of sonicated 'native' and 're-natured' xanthan have been investigated by size exclusion chromatography (SEC) with coupled multi-angle light scattering and viscosity detectors. 'Native' xanthan (NX) refers to xanthan dissolved in moderate ionic strength aqueous solution, which has not been exposed either to high temperature or very low ionic strength, and 're-nat...

Conformations of individual macromolecules of the biopolymer xanthan were investigated using atomic force microscopy (AFM). Xanthan from very dilute solutions (1 ppm) was allowed to adsorb onto freshly cleaved mica and examined using tapping mode AFM under ambient conditions. The secondary structure of xanthan was probed by heating the polymer and gradually cooling, which denatured and renature...

Xanthan gum is a biopolymer produced by Xanthomonas sp. XC6. In this study, xanthan gum is produced from potato starch using a stepwise bioprocess design. Potato starch is hydrolyzed using Bacillus sp. having amylase activity and 30.2 g/L reducing sugar was released, while Xanthomonas sp. XC6 can release only 14.5 g/L. Bacillus sp. hydrolyzed potato starch extract was further used as a carbon s...

A strategy for the unambiguous identification and selective quantification of xanthan gum and locust bean gum (LBG) in gelled food concentrates is presented. DNA detection by polymerase chain reaction (PCR) showed to be a fast, sensitive, and selective method that can be used as a first screening tool in intact gelled food concentrates. An efficient isolation procedure is described removing com...