Screening for wood-degrading enzymes in marine fungi

Forty marine and 15 terrestrial fungi in the Ascomycetes, Basidiomycetes, and Deuteromycetes were screened for presence and relative amount of enzymes involved in wood degradation (cellulases and redox enzymes) using seawater and deionized water media. Distribution of cellulases, laccase, tyrosinase, and peroxidase among marine and terrestrial groups of fungi was investigated. β-Glucosidase (C4) and endoglucanase (C3) were the most frequent enzymes (80 – 100% of the strains) of cellulose metabolism. Acid-swollen cellulose (C1) was generally more easily degraded than microcrystalline-dyed Avicel® (C2).All groups of strains showed relatively high percentages of cellulases C1, C3, C4, whereas production of cellulase C2 was lower. In comparison with Sporotrichum pulverulentum, a strongly cellulolytic terrestrial Deuteromycete, about 25% of the marine fungi tested showed the same high cellulase activity. Peroxidase was formed by nearly all strains tested at least on seawater medium; tyrosinase was the least frequent enzyme (20 – 35%). The presence of laccase was different among the various fungal systematic groups, reaching its highest percentages in the marine and terrestrial Basidiomycetes and the marine Ascomycetes, which mostly belong to the ecological groups of white-rot and soft-rot fungi, respectively. Enzymes involved in wood degradation were demonstrated in large number and sometimes considerable amounts in wood-inhabiting marine fungi. Key words: marine fungi, wood degradation, cellulase, phenoloxidases, screening, ecology.