Abstract

Textile industry is considered as one of the largest generators of toxic chemical waste water in India. Dyes released by the textile industries pose a threat to environmental safety. Recently, dye decolourization through biological means has gained momentum as these are cheap and can be applied to wide range of dyes. This review paper focuses on the bacterial biodegradation of toxic textile dyes. Along with the early history of dyes, the toxic effects of textile azo dyes also focused in this review. Various biological techniques for the biodegradation of textile dyes by microorganisms are clearly given in this review. The advantages of aerobic biodegradation over anaerobic degradation are also discussed in this review. The studies discussed in this paper indicate biological decolourization by bacteria has a great potential to be developed further as a decentralized wastewater treatment technology for small textile or dyeing units. However, further research work is required to study the toxicity of the metabolites of dye degradation and the possible fate of the utilized biomass in order to ensure the development of an eco-friendly technology.

Key words: Textile dye effluent, azo dyes, biodegradation and bacteria.