Degradation of black liquor by basidiomycetes fungi from native forest

Abstract

This project started at February 2012, collecting 24 isolates of fungi from native forest with the main aim to evaluate their potential for degradation and detoxification of black liquor. This waste, from pulp and paper industry, has environmental importance because its recalcitrant characteristics, like high BOD, QOD, lignin contents, phenolic compounds and pH 14. All fungi were screened according to its enzymatic activity by its growth and decolorization of vinasse and black liquor-agar solid medium (20 and 5%, respectively). In this study, the fungi growth will be verified in black liquor, starting from 10% of concentration, and its detoxification and degradation will be done by the methodology developed in the University of Toronto, Canada, during an internship from August 2012 to February 2013. In this internship we also looked for a detoxification of the black liquor and recovery of lignin. The mycelial growth and lignolytic enzymes activity, like laccases and peroxidases, will be analyzed during fungi growth in liquid state with agitation at 27 ºC, during 18 days. On each three days, supernatant samples will be taken and physicochemical analyses will be done (BOD, COD, metals, loss of color and pH), as well as biomass. In the same experiment, the lignin present in the degraded black liquor will be recovered by acid precipitation and together of its compounds, derived from enzymatic degradation, will be analyzed by size exclusion and gas chromatographic methods, respectively. Losses of toxicity of the black liquor enzymatically modified will be evaluated exposing aquatic organisms standardized in ecotoxicological assays, using Hydra attenuata and Daphnia magma. (AU)