Microbial degradation of an industrial azo-dye and FT-IR analysis

Abstract

The presence of dyes in wastewaters from the textile industry, even in concentrations of less than 1 mg/l, significantlyaffects the aesthetic properties and transparence degree of public effluents, with direct repercussions on theenvironment. Cerioporus squamosus White-Rot-Fungi (WRF) strain was used for bio-augmentation of MBBR carriers(consisting of a mix of 88% High Density Polyethylene, 5% talcum and 7% cellulose). Cerioporus squamosus, also oftenencountered as Polyporus squamosus, is a basidiomycete bracket fungus, able to cause “white rot” on decaying wood.The bio-functionalized carriers were used for treatment of a synthetic wastewater sample, of Bemacid ROT (Bezema)azo-dye. Azoic dyes represent one of the most important classes of synthetic dyes used in the textile industry,accounting for over 60–70% of the dyes used in this industry. In the case of reactive groups of azo dyes (-N=N-), dueto the low degrees of fixation on the fiber, there are losses of dyes in solution of up to 50%. Infrared spectral (FT-IR)analysis was carried out for determination of functional groups involved in biodegradative processes. Thus, the obtainedIR spectra, different from those of initial Bemacid ROT dye, the disappearance or decrease of the signal specific to azoicbonds from the initial sample, the formation of new functional groups, the disappearance of intermolecular hydrogenbonds simultaneously with increase of transmittance values for amino groups, resulted in highlighting the degradationof Bemacid ROT dye by the bio-augmented HDPE carriers.