ABSTRACT
The most important storage products of lichen photo- and mycobionts are free amino acids, proteins, polyols, glycosylated polyols, and polysaccharides. The glucans lichenan and isolichenan and the galactomannans, formerly called hemicelluloses, are present in lichens in relatively high amounts and presumably arise mainly from the predominant mycosymbiont. The product was named isolichenin and the strongly positive specific rotation indicated a linkages. Although mannose and galactose have been found frequently in lichen polysaccharides, there have been relatively few reports of galactomannans and of structural determinations carried out on them. Phycobiont precursors are converted into mannitol and, if the lichen continues photosynthesis, it is transposed into starch grains in the algal chloroplasts and, to a lesser extent, in grains of the fungus. The free and bound amino acids of lichens are of interest in evaluating the potential of lichens in nutrition.
