Bioaccumulation of the reactive textile dyes by Candida tropicalis growing in molasses medium

Abstract

Bioaccumulation of the reactive textile dyes, Remazol Blue, Reactive Black and Reactive Red, by the yeast species Candida tropicalis growing in molasses medium was studied in a batch system as a function of initial pH and initial dye concentration. The optimum pH value for bioaccumulation was determined as 3.0 for all the dyes tested. The maximum specific bioaccumulation capacity of C. tropicalis was 111.9 mg g −1 for Remazol Blue, 101.9 mg g −1 for Reactive Black and 79.3 mg g −1 for Reactive Red at approximately 700 mg l −1 initial dye concentration. Higher bioaccumulation percentages were observed at lower concentrations of all the dyes. In general, the increase in dye concentration inhibited the growth of yeast and caused a long lag period. Remazol Blue dye gave a considerably higher dye bioaccumulation percentage by the yeast among the dyes tested.