In Vivo and In Vitro Decolorization of Disperse Azo Dyes UsingAspergillusniger

Dyes can be considered the main contaminants of textile effluents, which have a heterocyclic complicated structure. Disperse dyes are one of the most commonly used classes of dyes with an insoluble nature and low molecular weight. In this study, the elimination of disperse dyes from aqueous medium was investigated by Aspergillus niger fungi using in vivo and in vitro methods. According to the in vitro decolorization results, the fungi showed high biosorption capacity for three different disperse dyes. At an initial dye concentration of 330 mg/l, the adsorption capacity of A. niger measured 225.3 mg/g for Disperse Yellow 23, 127.4 mg/g for Disperse Blue 183, and 176.3 mg/g for Disperse Red 1. Complete dye removal was achieved at lower initial concentrations after a 6-h operation. The results showed that the biosorption process favored acidic conditions, and the adsorption capacity and rate were higher at pH 4.5. Moreover, the kinetics of the adsorption process for all dyes followed the pseudo–second-order kinetic model. An in vivo decolorization test was also performed, in which A. niger was inoculated in a dye-containing medium to investigate the possible biodegradation of the dye by fungi during its growth. The biodegradation process was studied by Fourier transform infrared spectroscopy (FTIR) and high-performance liquid chromatography (HPLC) methods. The results obtained showed a maximum biodegradation of 49.77% for Disperse Red 1, whereas the decolorization for other dyes was mainly based on biosorption.