2.1.5 Lichenin
Synonym Moss starch; Lichen starch;
Biological Source Cetraria islandica (L.) Ach., Family: Parmeliaceae. It is known as Iceland Moss.
Description It is a cellulose like polysaccharide which occurs as a cell wall component in lichens. It is readily soluble in hot water to give rise to a colloidal solution. It is more rapidly hydrolyzed than cellulose. It produces cellobiose upon acetylation with acetic anhydride and sulphuric acid. It is a white powder.
On methylation followed by hydrolysis it yields 2,3,6-trimethylglucose as a major component and tetramethylglucose as minor one thereby suggesting that the chain present in lichenin is not branched at all as in cellulose.
Chemical Constituents The exact chemical structure of lichenin molecule is yet to be established; however, it has been indicated that it may contain both β-1, 4 and β-1, 6 linkages.