Decomposition of Lignocellulose from a Freshwater Macrophyte by Aero-Aquatic Fungi

Mineralization of uniformly radiolabeled$[{}^{14}{\rm C}]\text{lignocellulose}$and specifically radiolabeled$[{}^{14}{\rm C}\text{-lignin}]\text{lignocellulose}$from the freshwater sedge Carex walteriana by five aero-aquatic fungi was investigated. The extent of mineralization varied among the five species from 2.2 to 4.2% for the lignin component and from 3.3 to 20.6% for the polysaccharide component. The extent of mineralization of both lignin and polysaccharide moieties by a mixed culture of the five fungi were generally markedly lower than by pure cultures, possibly due to the production of antimicrobial compounds. Spirosphaera floriformis, the most active strain in lignin as well as in polysaccharide mineralization, degraded ferulic acid faster than p-coumaric acid. Decomposition of Carex walteriana lignocellulose by this strain resulted in decreased cinnamyl/vanillyl (C/V) and syringyl/vanillyl (S/V) ratios.