Cell wall structure of mushroom sclerotium (Pleurotus tuber regium): Part 1. Fractionation and characterization of soluble cell wall polysaccharides

The cell wall structure of mushroom sclerotium was investigated by a fractionation of its soluble cell wall polysaccharides followed by chemical, physico-chemical and microscopic analyses. The present results suggest that cell wall structure of Pleurotus tuber regium sclerotium contains three main layers: an outer layer of glycoproteins, a middle layer of hyper-branched glucans and an inner layer of complex between hyper-branched glucan and chitin. The structure of the hyper-branched glucans were elucidated by the methylation analysis to be composed of -> 1)-Glcp-(4 -> linkages as the backbone with some -> 1)-Glcp(6 -> linkages existed in the side chains, while some -> 1)-Glcp-(3 -> linkages might exist in the backbone or side chains. SEC-MALLS analysis revealed that hyper-branched beta-glucans had a M-w ranging from 1.4 to 5.2 x 10(6) g/mol and R.M.S. radius ranging from 26 nm to 38.5 nm. SEM and AFM further showed that hyper-branched beta-glucans were spherical in shape when dispersed in water. (c) 2013 Elsevier Ltd. All rights reserved.