The evaluation of white rot fungi in the decoloration of textile dyes

Of the five species of white rot fungi evaluated for their ability to decolorize Amaranth, Remazol Black B, Remazol Orange, Remazol Brilliant Blue, Reactive Blue, and Tropaeolin O in agar plates, Bjerkandera sp. BOS55, Phanerochaete chrysosporium, and Trametes versicolor displayed the greatest extent of decoloration. In static aqueous culture, the three cultures formed fungal mats which did not decolorize any dye beyond some mycelial sorption. When agitated at 200 rpm, the biomass grew as mycelial pellets. Bjerkandera sp. BOS55 pellets decolorized only Amaranth, Remazol Black B, and Remazol Orange. P. chrysosporium and T. versicolor pellets were capable of decolorizing most dyes with decoloration by T. versicolor being several times more rapid. Batch cultures of Bjerkandera sp. BOS55 and P. chrysosporium had a limited ability to decolorize repeated dye additions; however, T. versicolor rapidly decolorized repeated additions of the different dyes and dye mixtures without any visual sorption of any dye to the pellets. The choice of buffer had a profound effect on pH stability upon dye addition, and consequently, decoloration. The use of 2,29-dimethylsuccinic acid allowed for excellent pH control and resulted in high decoloration ability. © 1999 Elsevier Science Inc.