Abstract:
Enzyme based degradation of organic pollutants is a promising detoxifying approach due to the promiscuous nature of the
enzyme, efficiency, cost effective and ecofriendly. In the present study, we have carried out detailed decoloration and
degradation studies on a model triphenyl methane group of dyes (Malachite Green dye (MG)) using a newly isolated enzyme
from Bacillus cereus KM201428 under the static condition. Biodegradation of dyes was monitored by UV-VIS
spectrophotometer and the resultant metabolites analyzed by Liquid Chromatography–Hybrid Quadrupole Time of Flight Mass
Spectrometry (LC–QToF-MS) and Gas Chromatography/Mass Spectrometry (GC - MS). Metabolite analysis results revealed that
enzymatic degradation of MG dye resulted in complete mineralization and benzene ring-removal; the latter known for organic
dye toxicity. Kinetic study results revealed that first-order kinetic model was best applicable for describing MG dye decoloration.
Michaelise-Menten kinetics, Lineweaver–Burk plot and Eadie-Hofstee plot models were used to establish the kinetic parameters
for the dye decoloration. Lineweaver–Burk plot provided the best theoretical correlation of the experimental data with maximum
rate (Vmax) of 17.70 mg l-1h-1 and Michaelis constant (Km) of 124 mgl-1. Results provide evidence that crude enzyme from
Bacillus cereus strain KM201428 offers an effective, renewable, ecofriendly and affordable biotechnology for treatment of
industrial effluents polluted with organic dye.
