Resumo

SALAS VEIZAGA, Daniel Martin; MORALES BELPAIRE, Isabel  e  TERRAZAS SILES, Enrique. Decolorizing capacity of Coriolopsis polyzona, Pycnoporus sp. and Penicillium sp. on Reactive Black 5 under  different culture conditions. BIOFARBO [online]. 2012, vol.20, n.1, pp. 41-48. ISSN 1813-5363.

During the textile dyeing process, a part of the dyes is eliminated in effluents, possibly polluting rivers. An alternative for the degradation of these dyes is the use of extracellular enzymes produced by fungi, mainly those belonging to the “White-rot fungi” group. The present study evaluated the decolorizing capacity of three fungal strains on Reactive Black 5. We followed de decolorization of the dye in solid and liquid culture media at different temperatures and in the presence of enzymatic inhibitors. The decolorizing capacity of the Coriolopsis polyzona and Pycnoporus spp. strains varied with temperature. The C. polyzona strain showed higher capacity at 32°C, decreasing with lower temperatures. The Pycnoporus strain showed higher capacity for temperatures under 25°C. Temperature had little effect on the decolorizing capacity of Penicillium sp. strains. The enzymatic inhibitors tested were ammonium monovanadate, which caused partial inhibition of the decolorizing process, and cadmium nitrate, which caused total inhibition of the process. Cadmium nitrate also showed toxicity on mycelia and caused precipitation of the dye. These results suggest that for C. polyzona and Pycnoporus sp. strains, decolorization is caused by biodegradation, while the Penicillium sp. strain caused decolorization by bioadsorption. This could explain the different behaviors of the strains with temperature. The effect of the inhibitors can be caused by enzyme inactivation as well as by toxicity on fungi. In effluents that contain the tested metals, the decolorization process was inhibited.

Palavras-chave : Decolorization; Reactive Black 5; Coriolopsis polyzona; Pycnoporus spp.; Penicillium spp..