In the laboratory, the white rot fungus Phanerochaetechrysosporium degrades numerous organic pollutants. Lack of aslow-release delivery system to toxic waste sites, for this and other fungi,however, constitutes an important barrier to practical implementation. Inthis study, the use of calcium alginate as an encapsulant for mycelia wasinvestigated; samples were in the form of pellets 1-3 mm in diameter. Whenrefrigerated, alginate-embedded mycelia of P. chrysosporium wereviable for one year, both with and without nutrient supplementation. At roomtemperature, in the absence of nutrient supplementation, viability decreasedsharply within 2 months. Addition of sawdust or corncob grits extended theviability of alginate-embedded mycelia; nevertheless, after 9 months onlyabout 20% of the pellets stored at room temperature yielded fungalgrowth. Spores of P. chrysosporium, embedded in alginate pelletstogether with corncob grits, gave 75% viability after 9 months ofstorage at room temperature. Alginate-embedded mycelia were used in Petriplate toxicity tests with 2,4,6-trinitrotoluene (TNT) and gave more rapid andreproducible results than tests performed with mycelial plugs. Theseexperiments demonstrated the feasibility of encapsulating P.chrysosporium in calcium alginate pellets, thus providing a potentialmethod of delivering white rot fungi to toxic waste sites, as well as fordeveloping a system of standardized toxicity testing in plate assays.