CONICET | Buscador de Institutos y Recursos Humanos

Textile dyes are engineered to be resistant to environmental conditions. During the last years the treatment of textile dye effluents has been the focus of significant research because of the potentially low cost of the process. Mechanisms of biological textile dyes decolourization greatly depend on the dye chemical structure, the employed microorganisms and media culture composition. In this study, decolourization of the diazo dye Reactive Black 5 was carried out by the native yeast Trichosporon porosum 4029. The effect of peptone, CaCl2, KH2PO4, MgSO4, glucose, yeast extract and (NH4)2SO4 were initially studied in a seven factor Plackett?Burman design. Only glucose, yeast extract and (NH4)2SO4 showed a significant effect on dye decolourization; whereas peptone, CaCl2, KH2PO4 and MgSO4 could be safely excluded from decolourization medium. Subsequently, a three factor full factorial design was employed in order to study the effect and interactions between glucose, yeast extract and (NH4)2SO4 concentration on dye decolourization. In optimized medium, glucose and (NH4)2SO4 final concentrations were decreased to 10 g/l and 1.25 g/l, whereas yeast extract final concentration was reduced to a 1 g/l. Those values represent a 60 % reduction for the initial concentration of yeast extract and 50 % for the other two components. Under those optimized conditions, Trichosporon porosum was able to decolourize almost completely 200 mg/l of Reactive Black 5 within 24 h. Results has allowed the formulation of a new decolourization medium, simpler and greatly reduced in costs, for its future use in bioremediation processes.