The laboratory-isolated strains Pseudomonas aeruginosa, Rhodobacter sphaeroides, Proteus mirabilis, Bacillus circulance, NAD 1 and NAD 6 were observed to be predominant in the bacterial consortium responsible for effective decolorization of the azo dyes. The kinetic characteristics of azo dye decolorization by bacterial consortium were determined quantitatively using reactive vinyl sulfonated diazo dye, remazol black-B (RB-B) as a model substrate. Effects of substrate (RB-B) concentration as well as different substrates (azo dyes), environmental parameters (temperature and pH), glucose and other electron donor/co-substrate on the rate of decolorization were investigated to reveal the key factor that determines the performance of dye decolorization. The activation energy (E-a) and frequency factor (K-0) based on the Arrhenius equation was calculated as 11.67 kcal mol(-1) and 1.57 x 10(7) mg l g MLSS-1 h(-1), respectively. The Double-reciprocal or Lineweaver-Burk plot was used to evaluate V-max, 15.97 h(-1) and K-m, 85.66 mg l(-1). The two-stage anoxic-oxic reactor system has proved to be successful in achieving significant decolorization and degradation of azo dyes by specific developed bacterial consortium with a removal of 84% color and 80% COD for real textile effluents vis-a-vis >= 90% color and COD removal for synthetic dye solution. (c) 2008 Elsevier B.V. All rights reserved.