Because of the cheaical stability of the dye compounds and the difficulties of treating dyeing wastewaters by conventional processes, the reaoval of colour from textile and/or dyeing wastewaters is one of the major environmental problems. Reactive dyes are the largest class of dyes, and also one of the commonly used dyes with great variety of colours.
Bacteria and yeasts with the ability of colour adsorption were isolated from activated sludge and soil samples. Eleven reactive dyes (100 mg/l) with different colour spectra were tested; the colour removal efficiencies ranged from 12.9-94.3 %, among these dyes, RG, a red colour dye, was effectively adsorbed by the isolated Aeromonas biomass. The specific adsorption capacity was 27.41 (mg dye/g dried cell), the ability to remove colour was 60.3%. The adsorption isotherm follows the Freundlich model, and the main adsorption site occurred at the cell wal1 portion.