THE EXTRACELLULAR POLYSACCHARIDE OF PICHIA (HANSENULA) HOLSTII NRRL Y-2448 - THE PHOSPHORYLATED SIDE-CHAINS

The exopolysaccharide produced by Pichia (Hansenula) holstii NRRL Y-24 48 is composed of a phosphomannan core to which oligosaccharide dieste r phosphate side chains are appended. The oligosaccharides of the side chains were released as oligosaccharide phosphates and neutral oligos accharides by mild hydrolysis with aqueous acetic acid and aqueous hyd rogen fluoride, respectively. The liberated oligosaccharide phosphates were studied by NMR spectroscopy and by electrospray and fast atom bo mbardment mass spectrometry. The structures of the neutral oligosaccha rides were determined by 1D and 2D NMR spectroscopic experiments. Furt her insight into the length of the side chains was obtained from a mat rix assisted laser desorption ionisation-time of flight mass spectrome tric study of high and low molecular weight fragments obtained from pa rtial acid hydrolysis of the native polysaccharide. (C) 1998 Elsevier Science Ltd. All rights reserved.