Decolorization and detoxification of extraction-stage effluent from chlorine bleaching of kraft pub by Rhizopus oryzae

Rhizopus oryzae, a zygomycete, was found to decolorize, dechlorinate, and d etoxify bleach plant effluent at lower cosubstrate concentrations than the basidiomycetes previously investigated, With glucose at 1 g/liter, this fun gus removed 92 to 95% of the color, 50% of the chemical oxygen demand, 72% of the adsorbable organic halide, and 37% of the extractable organic halide in 24 h at temperatures of 25 to 45 degrees C and a pH of 3 to 5. Even wit hout added cosubstrate the fungus removed up to 78% of the color, Monomeric chlorinated aromatic compounds were removed almost completely, and toxicit y to zebra fish was eliminated. The fungal mycelium could be immobilized in polyurethane foam and used repeatedly to treat batches of effluent. The re sidue after treatment was not further improved by exposure to fresh R, oryz ae mycelium.