An indigenous bacterium; Klebsiella pneumoniae strain AHM was acclimated from the vicinities exposed to the frequent discharge of untreated textile recalcitrant compounds. The bacterium was employed to decolorize and mineralize a sulfonated textile colorant; reactive orange 16 (RO16). An equation for quantifying the average mineralization rate, AMI(RO16) mu M/min of the liberated aromatic amines was established during the biotransformation. The strain had average decolorization and mineralization rate (ADR(RO16) and AMI(RO16)) of 333.33 mu g/min and 0.46 mu M/min respectively, when incubated with 50 mg/L RO16 under static condition. The inducible oxidoreductases along with the spectral and chromatographic analyses proved that the biotransformation was due to the metabolism of K. pneumoniae strain AHM. The toxicological assessment of plant growth parameters and the chlorophyll concentrations of Phaseolus mungo, Triticum aestivum and Sorghum bicolor seedlings revealed the reduced toxic nature of the mineralized products. (C) 2017 Elsevier Ltd. All rights reserved.