Biotreatment of tannin-rich beer-factory wastewater with white-rot basidiomycete Coriolopsis gallica monitored by pyrolysis/gas chromatography/mass spectrometry

Some fractions of beer-factory wastewaters represent an important environmental concern owing to their high content of polyphenols and dark-brown color. The capacity of Coriolopsis gallica to preferentially degrade lignin has been successfully applied in our laboratory to the biotreatment and decolorization of paper-industry effluents. In this work, the ability of this white-rot fungus to degrade high-tannin-containing wastewaters is evaluated. Under all the conditions studied, effluent decolorization and chemical oxygen demand reduction achieved by C. gallica at day 12 of incubation were close to 50 and 65%, respectively. No adhesion of dark color to the fungal mycelium was observed suggesting that decolorization could be ascribed to C. gallica degradation systems. Mycelium dry-weight values showed that C. gallica is tolerant to relatively high tannin content present in the effluent samples. In the sample containing the highest effluent concentration (60% v/v), dry-weight values suggested an inhibition of fungal growth at day 6 of incubation and a further adaptation of the fungus to the stressing tannin effect at day 12 of fungal treatment. Pyrolysis/gas chromatography/mass spectrometry results showed a decrease of polyphenols pyrolysis products, mainly phenol and guaiacol, with the incubation time. All these results indicate the potential use of C. gallica in bioremediation of tannin-containing industrial wastewaters and in other applications where a reduction in polyphenols content is required.