SOFT-ROT FUNGAL DEGRADATION OF LIGNIN IN 2700-YEAR-OLD ARCHAEOLOGICALWOODS

Soft-rot fungal degradation of archaeological wood was investigated by comparing the micromorphological characteristics, elemental compositi ons and monomeric and dimeric phenols derived from CuO oxidation of li gnins in degraded boxwood, maple, juniper and pine woods from Tumulus MM, Turkey, thought to be the ancient tomb to King Midas dated 2700 ye ars before present (BP). Chemical compositions of these soft-rotted ar chaeological woods were compared to those of modern undegraded counter parts and to those of contemporary white- and brown-rotted woods. The degraded angiosperm woods showed Type 1 (cavity) and Type 2 (erosive) forms of soft-rot, whereas the degraded gymnosperm samples exhibited o nly Type 1 decay. All soft-rotted woods contained higher weight percen tages of ash and nitrogen than their fresh counterparts. Polysaccharid es were preferentially attacked by soft-rot fungi as indicated by decr eased atomic ratios of hydrogen/carbon in all degraded woods and lower atomic ratios of oxygen/carbon in remnant boxwood, maple, and pine wo ods. In addition, soft-rot fungi extensively attacked lignin as eviden ced by the lower carbon-normalized yields of lignin monomers from most degraded samples. All soft-rotted woods had elevated acid/aldehyde ra tios indicative of oxidative microbial degradation of remnant lignin s idechains. Soft-rot degradation resulted in greater carbon cross-linki ng of the remnant lignin and enrichment of ring-ring dimers in the deg raded angiosperm samples, indicating preferential attack of sidechain- linked structures within the lignin polymer. While soft-rot fungi shar e some degradative characteristics with both white- and brown-rot fung i, the physical and chemical effects of soft-rot degradation are uniqu e.