Extracellular polysaccharides of Erwinia futululu,a bacterium associated with a fungal canker disease of Eucalyptus spp

Extracellular polysaccharides (EPSs) produced by an Erwinia spp. associated with a fungal canker disease of Eucalyptus were fractionated into two polysaccharides, one that was identified with that produced by Erwinia stewartii. The other has a similar structure, but with one terminal Glc residue replaced by pyruvic acid to give 4,6-O-(R)-1-carboxyethylidene)-Galp. Their structures were determined using a combination of chemical and physical techniques including methylation analysis, periodate oxidation, low-pressure gel filtration and anion-exchange chromatographies, high-pH anion-exchange chromatography, mass spectrometry and 1D and 2D 1H NMR spectroscopy. The new polysaccharides, identified as EPS Futululu FF-1 and FF-2, have the following structures:The molecular weights of the polysaccharides range from 1.3-2.1x10(6) and their hydrodynamic properties are those of polydisperse, polyanionic biopolymers with pseudoplastic, non-thixotropic flow characteristics in aqueous solutions.