Characterization of storage cell wall polysaccharides from Brazilian legume seeds and the formation of aqueous two-phase systems.

Cell wall storage polysaccharides from Brazilian legume seeds of Dimorphandra mollis, Schizolobium parahybum (galactomannans), Copaifera langsdorffii, Hymenaea courbaril (xyloglucans) and the galactan from cotyledons of the Mediterranean species Lupinus angustifolius were extracted and their apparent molecular masses were determined by high-performance size exclusion chromatography analysis. They were, to a large degree, polydisperse, showing molecular masses that varied from 100,000 to 2,000,000. Polyethylene glycol (PEG, 1500, 4000, 6000 and 8000), sodium citrate and dextran (73,000, 60,000-90,000, 505,000 and 2,000,000) were used for investigating phase formation with the seed polysaccharides. Galactomannans and xyloglucans demonstrated phase formation with sodium citrate concentrations lower than 30%, as well as dextrans and polyethylene glycol, and formed gels in the presence of high concentrations of sodium citrate (above 30%). Galactan did not promote phase formation with any of the reagents used. On the basis of the results obtained, the possibility of using legume seed polysaccharides for the partitioning and purification of polysaccharide enzymes in aqueous two-phase systems is suggested.