Suppression of bioremediation by Phanerochaete chrysosporium by soil factors

Abstract

The timing of onset of mineralization of pyrene by Phanerochaete chrysosporium correlated with the production of ligninase activity as monitored by the decolorization of the polymeric dye Poly R-478. A layer of native soil decreased the growth of P. chrysosporium by visual assessment of hyphal mass and measurement of ergosterol, a fungal membrane sterol. The native soil layer slowed the production of ligninase as determined by Poly R-478 decolorization and the rate of mineralization of pyrene was decreased. Inhibition of pyrene mineralization was also observed with layers of sterilized silt and clay but not by sand. Mineralization, fungal growth and rate of decolorization of the dye were improved when the native soil was sterilized by autoclaving. Suspensions of the native soil contained a consortium of bacteria and fungi. Several of the bacteria were antagonistic to the growth of P. chrysosporium on solid medium. The onset of dye decolorization by P. chrysosporium on a nitrogen-limited medium was delayed by certain bacteria. These findings suggest that in certain soils, bioremediation by P. chrysosporium could be suppressed by indigenous soil microbes as well as by the abiotic features of the soil composition.