The structure of the exocellular polysaccharide produced by Rhodococcus sp. RHA1

Rhodococcus sp. RHA1 is a Gram-positive actinomycete capable of metabolizing a wide spectrum of organic compounds whose survival in chemically hostile environments is believed to be in part due to the production of an exocellular polysaccharide (EPS). In order to investigate the functional nature of the EPS, its structure was determined using a combinatory approach including hydrolysis, composition, and methylation, analysis methods, as well as 2D 1H and 13C NMR spectroscopy. The EPS was found to be a high-molecular-mass polymer of a repeating tetrasaccharide unit composed of d-glucuronic acid, d-glucose, d-galactose, l-fucose and O-acetyl (1:1:1:1:1), and has the structure: