Original article

Dyeing of cotton with sulfur dyes using alkaline protease Priyadarshi Jaruhar and JN Chakraborty Sulfur dyes are applied on cotton to produce deep shades at low cost; they provide excellent color fastness, except against chlorinating agents. Sodium sulfide used as a reducing and solubilizing agent in this dyeing process is highly toxic and produces unhygienic hydrogen sulfide. In this study, alkaline protease was used in place of sodium sulfide to see if the latter could be substituted with the former, because of its hydrolytic and reducing nature in an alkaline bath. The study revealed that alkaline protease was quite effective in this regard and capable of substituting sodium sulfide with com-parable dye strength of dyed cotton along with promising color fastness. Keywords sulfur dye, sodium sulfide, alkaline protease, dye strength, colorfastness While dyeing cotton with sulfur dyes, it has been of commercial importance to produce deep shades, such as black, navy blue, khaki and green, with all-roun