Evaluation of decolorization abilities of some textile dyes by fungal isolates

Abstract

Nine previously isolated and identified fungal strains from post-finishing textile effluents were investigated for their decolorisation ability of three Bemacid textile dyes, in aqueous solution. Identified fungal isolates belong to the following groups: Trichoderma parceramosum, Trichoderma reesei, Trichoderma longi, Polyporus squamosus and Fusarium oxysporum, along with Aspergillus niger (IMI 45551), used as a reference collection strain. Maximum absorbance peaks in visible region, for each dye, were assessed spectrophotometrically and dye residual concentration reduction were assessed at 500nm for Bemacid ROT, 370nm Bemacid GELB and 590nm Bemacid BLAU. Purity screening of the dyes was assessed by Thin Layer Chromatography (TLC), and decolorisation assays were carried out in nutritive media, in 5 simultaneous batches, for 3, 5, 9, 12 and 15 days, with each batch run in triplicate, and results expressed as mean of triplicate values for each combination of strain and dye. Quantitative analysis of solutions decolorisation was carried out via UV-VIS spectrophotometry assessment, quantifying decolorisation degree over post-incubation period at 29°C, each dye residual concentration reduction ranging from 20.98% to 98.02% for Bemacid ROT, 43.5% to 96.06% for Bemacid GELB and 35.68% to 98.38% for Bemacid BLAU, thus promoting biological approach of wastewater treatment with the aid of filamentous fungi as an efficient, cost effective and environmental friendly solution.