Lindow man, tollund man and other peat-bog bodies: The preservative and antimicrobial action of Sphagnan, a reactive glycuronoglycan with tanning and sequestering properties

Abstract The tanning reaction that contributes to the preservation of animal tissues by peat consists of a Maillard reaction between the free amino-groups of collagen and reactive carbonyl groups in a soluble glycuronoglycan (‘sphagnan’) containing residues of d - lyxo -5-hexosulopyranuronic acid. Sphagnan is a complex, pectin-like material which is covalently linked to cellulosic and amyloid-like chains in living Sphagnum moss, but slowly liberated by autohydrolysis into the ambient water as the dead moss is converted into peat. It is a precursor of aquatic humus from Sphagnum peat, and the tanning of adventitious collagen in animal remains is only one manifestation of the continuous incorporation of ammonia, aminoacids and polypeptides from a wide variety of sources into the structure of the humic acid molecule. Sphagnan can also suppress microbial activity by reacting with exo-enzymes and sequestering essential, multivalent metal cations.