Evaluation of individual fungal species and their co-culture for degrading a binary mixture of dyes under solid-state fermentation

Abstract

Description of the subject. In recent years, biological methodologies, such as solid-state fermentation, have acquired a great relevance for bioremediation of complex molecules because of their efficiency and low environmental impact. Specifically, the use of white-rot fungi in different biotechnological processes has emerged as a promising strategy given their broad enzymatic potential. Objectives. Evaluation of three individual fungal species, as well as various fungal consortia of these species, for the degradation of a mixture of dyes, brilliant blue – allura red, through solid-state fermentation. Method. The species Pleurotus pulmonarius, Pleurotus ostreatus and Trametes versicolor were assessed, both individually, and in their binary consortia. The interaction between the mycelia of the different white-rot fungi was taken into account as a criterion for using their consortia to degrade the mixture of pollutants under solid conditions. The dyes were adsorbed onto the agro-industrial by-products flower stems and corncob. The fermentative process was carried out over 20 days, after which the degradation percentage was quantified by UV-Vis spectroscopy. Results. The highest degradation percentage was obtained after fermentation by T. versicolor alone. This species reached an average degradation of 79.57% of the binary mixture of dyes, brilliant blue – allura red. Meanwhile, the best consortium, composed of P. ostreatus and T. versicolor, achieved a degradation of 63.24%. Conclusions. These results suggest that the use of fungal consortia, in solid media, does not always lead to a synergy between species for improved dye degradation by the integrated strategy that includes the processes of adsorption and solid-state fermentation. Instead, competition for space and nutrients associated with growth on a solid substrate could decrease the degradation efficiency.