COMPETITION OF PLEUROTUS SP AND DICHOMITUS SQUALENS WITH SOIL-MICROORGANISMS DURING LIGNOCELLULOSE DECOMPOSITION

If has been suggested that white-rot fungi might be used in the biorem ediation of soil contaminated with highly resistant pollutants. Under field conditions the fungus must not only be able to survive, but also be biologically active in the face of competition from the native soi l microflora. In this study the competitive saprophytic capabilities o f two species of white-rot fungi were evaluated in solid-state straw c ultures in the presence of soil microorganisms. Pleurotus sp. strain B hutan strongly inhibited growth of soil bacteria. Pleurotus cultures w ith or without soil microflora showed only small differences in the pa rameters: decomposition of organic matter decomposition of lignin and pH, thus showing this fungus to be highly competitive with respect to the soil microorganisms. In contrast, in mixed cultures of Dichomitus squalens with soil microorganisms, bacterial growth was even higher th an in sterile straw, while the decomposition of organic matter especia lly of lignin, was much lower than in pure cultures of the fungus thus indicating that the activity of the fungus, and perhaps even its abil ity to survive, were suppressed by the soil microorganisms. (C) 1997 E lsevier Science Ltd.