New structural insights into the cell-wall polysaccharide of the diatom Phaeodactylum tricornutum

• Published in: Algal research (Amsterdam) 2017-09, Vol.26, p.172-179
• Main Authors: Le Costaouëc, Tinaïg, Unamunzaga, Carlos, Mantecon, Lalia, Helbert, William
• Format: Article
• Language: English
• Subjects: Life Sciences; Mass spectrometry; Microalgae; NMR spectroscopy; Phaeodactylum tricornutum; Polysaccharide; Structure determination
• ISSN: 2211-9264; 2211-9264
• DOI: 10.1016/j.algal.2017.07.021

The cell wall of diatoms is composed of silica and organic matter, including protein, long-chain polyamines and polysaccharides. The main polysaccharide, a sulphated glucuronomannan, has been observed in many diatoms suggesting that it plays an important role in cell-wall biogenesis. We extracted and purified the polysaccharide, prepared oligosaccharide series and analysed the structure of poly- and oligosaccharides using chromatography and NMR spectroscopy methods. Our results show that the backbone of the polysaccharide is predominantly a linear poly-α-(1→3) mannan decorated with sulphate ester groups and β-D-glucuronic residues. •The main cell wall polysaccharide of Phaeodactylum tricornutum found in numerous diatoms species was purified.•Series of oligosaccharides were produced by mild acid hydrolysis and purified.•Oligo- and polysaccharides were fully analysed by chemical and spectroscopy methods.•The structure of P. tricornutum cell wall polysaccharide is a sulfated α-mannan decorated with glucuronic residues.