Open AccessA (1→6)‐linked β‐mannopyrananan, pseudonigeran, and a (1→4)‐linked β‐xylan, isolated from the lichenised basidiomycete Dictyonema glabratum
Author(s) -
Carbonero Elaine R,
Sassaki Guilherme L,
Gorin Philip A.J.,
Iacomini Marcello
Publication year - 2002
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2002.tb11005.x
Subject(s) - mannan , xylan , chemistry , glucan , polysaccharide , aqueous solution , chromatography , residue (chemistry) , biochemistry , organic chemistry
Extraction of Dictyonema glabratum with hot 2% (w/v) aqueous KOH at 100°C, followed by neutralisation and freeze‐thawing, gave an insoluble glucan. The residue was further extracted by a similar process, but with hot 10% (w/v) aqueous KOH, furnishing a mixture of glucan, mannan and xylan. The mannan and xylan were obtained via precipitation of its copper complex with Fehling's solution, leaving the glucan in the supernatant. The insoluble complex was finally purified through gel permeation chromatography. Methylation analysis, one‐ and two‐dimensional nuclear magnetic resonance examination showed the polysaccharides to be a (1→3)‐linked α‐glucan (pseudonigeran) and a (1→4)‐linked β‐xylan, both not previously encountered in lichens, and a newly discovered (1→6)‐linked β‐mannan.