Degradation of a tannery and textile dye, Navitan Fast Blue S5R by Pseudomonas aeruginosa

The degradation of Navitan Fast Blue S5R, a very important commercial diazo dye in the tannery and textile industries was investigated. Pseudomonas aeruginosa decolourized this dye at concentrations upto 1200 mg l(-1) and the organism was also able to decolourize various other tannery dyes at different levels. The organism required ammonium salts and glucose to co-metabolize the dye. Organic nitrogen sources did not support appreciable decolourization whereas, combined with inorganic nitrogen (NH4NO3) there was an increased effect on both growth and decolourization. Decolourization of this dye started when the organism reached late exponential growth phase and after 24 h of incubation nearly 90% of 100 mg l(-1) of the dye was decolourized. An oxygen insensitive azoreductase was involved in the decolourization mechanism. HPLC analysis confirmed the formation of metanilic acid from the dye, which on further incubation was completely metabolized under shaken culture condition.