Use of natural and artificial seawater for investigation of growth, fruit body production, and enzyme activities in marine fungi

Investigation of marine fungi suffers from an often inadequate comparability of methods and results, e.g., the use of natural as opposed to artificial seawater. Consequently, several marine fungi of different systematic positions were tested for growth, enzyme activity, and fructification on solid media with natural and artificial seawater. Growth as colony diameter and production of enzymes by the basidiomycete Halocyphina villosa and the ascomycete Lulworthia sp. were compared on both media. In all cases the results showed either no difference or only minor quantitative differences. Investigation of further species (two ascomycetes, one basidiomycetous yeast, two deuteromycetes) and other enzymes also showed no differences between the two media with the exception of three cases. Fructification in Halocyphina villosa occurred on both types of seawater. Addition of boric acid in natural concentrations to the artificial seawater medium had no effect on the growth of nine marine fungi. Artificial seawater medium gives comparable results to natural seawater in experiments with marine fungi, results in better comparability and reproducibility of experiments, and is often cheaper and easier to obtain. Key words: natural seawater, artificial seawater, marine fungi, growth, enzymes, fruit bodies.