Structural analysis of an extracellular polysaccharide produced by a benzene tolerant bacterium, Rhodococcus sp 33

Rhodococcus sp. 33 can tolerate and efficiently degrade various concentrations of benzene, one of the most toxic and prevailing environmental pollutants. This strain produces a large quantity of extracellular polysaccharide (33 EPS), which plays an important role in the benzene tolerance in Rhodococcus sp. 33, especially by helping the cells to survive an initial challenge with benzene. This EPS has been reported to be composed of D-galactose, D-glucose, D-mannose, D-glucuronic acid, and pyruvic acid at a molar ratio of TO understand the protective effect of 33 EPS, we determined its chemical structure by using H-1 and C-13 NMR spectroscopy including 2D DQF-COSY, TOCSY HMQC, HMBC, and NOESY experiments. The polysaccharide was shown to consist of tetrasaccharide repeating units with the following structure: [GRAPHICS] (c) 2006 Elsevier Ltd. All rights reserved.