Adaptation of the white-rot basidiomycete Panus tigrinus for transformation of high concentrations of chlorophenols

Abstract.

During feed-batch cultivation of the white-rot fungus Panus tigrinus in a 5-l bioreactor on N-limited medium, 100, 200, 500, 1,000 and 2,000 mg 2,4,6-trichlorophenol (2,4,6-TCP) l^–1 were added sequentially after 90% removal of the previous portion of the toxicant. The addition of 500 mg 2,4,6-TCP l^–1 without preliminary adaptation killed the culture. The addition of 300 mg 2,4,6-TCP l^–1 without prior adaptation resulted in its slower removal than removal of 2,000 mg 2,4,6-TCP l^–1 by this adapted culture. After adaptation of P. tigrinus to 2,4,6-TCP in a 72-l bioreactor, the mixture of 2,4-dichlorophenol, 2,4,6-TCP, and pentachlorophenol, each at 500 mg l^–1, was totally removed over 3 weeks. No lignin peroxidase activity was found in the course of cultivation of the fungus. Laccase activity was suppressed by addition of 2,4,6-TCP. Mn-peroxidase was found to be responsible for transformation of the chlorophenols. As final products of the process, several newly formed aromatic polymers, both chlorinated and non-chlorinated, were found in the culture liquid.