A Review on Microbial Decolorization and Degradation of Dyes

Dye is any colored organic compound that absorbs light strongly specifically in the visible region and can firmly attach to the fibers by the virtue of physico-chemical bonding between the dye and fiber. For commercial usage a dye should be fast to light, rubbing and water. Dyes and dyestuffs are most widely used in textile manufacturing. Wastewater from the textile industry is generally full of complex mixture of various polluting substances including dyes and certain heavy metals. Thus, textile industry too gets foremost attention by environmentalists due to consumption of huge volume of water, dyes and chemicals for diverse processing of textiles and pose problems like other industrial pollutants. Textile effluents mainly comprise of carcinogenic aromatic amines, dyes, organic and inorganic materials. Elimination of dyes from textile industrial effluents by various physico-chemical as well as biological methods is presently operational. The physico- chemical methods are expensive and less effective for complete removal of colored effluent, whereas the biological decolorization of textile effluents is getting much importance due to cost effective process but on the contrary is a bit time consuming. Recent promising research on biological decolorization and degradation of textile effluent has showed that diverse group of microorganisms are capable of decolorizing and degrading broad range of dyes. The factors affecting decolorization and biodegradation of dye compounds such as pH, temperature, dye concentration, effects of carbon and nitrogen sources need optimization. Some of these parameters involved in microbial decolorization of dyes have been discussed.