Alkali, thermo and halo tolerant fungal isolate for the removal of textile dyes

In the present study potential of a fungal isolate Aspergillus lentulus FJ172995, was investigated for the removal of textile dyes. The removal percentages of dyes such as Acid Navy Blue, Orange-HF, Fast Red A, Acid Sulphone Blue and Acid Magenta were determined as 99.43, 98.82, 98.75, 97.67 and 69.98, respectively. None of the dyes inhibited the growth of A. lentulus. Detailed studies on growth kinetics, mechanism of dye removal and effect of different parameters on dye removal were conducted using Acid Navy Blue dye. It was observed that A. lentulus could completely remove Acid Navy Blue even at high initial dye concentrations, up to 900 mg/L. Highest uptake capacity of 212.92 mg/g was observed at an initial dye concentration of 900 mg/L. Dye removing efficiency was not altered with the variation of pH; and biomass production as well as dye removal was favored at higher temperatures. Dye removal was also efficient even at high salt concentration. Through growth kinetics studies it was observed that the initial exponential growth phase coincided with the phase of maximal dye removal. Microscopic studies suggest that bioaccumulation along with biosorption is the principle mechanism involved in dye removal by A. lentulus. Thus, it is concluded that being alkali, therm and halo tolerant, A. lentulus isolate has a great potential to be utilized for the treatment of dye bearing effluents which are usually alkaline, hot and saline. (C) 2010 Elsevier B.V. All rights reserved.