Decolorization of the azo dye methyl red by an isolated bacterium Enterobacter hormaechei strain CUIZ1

Microorganisms play a major role in the degradation of organic matter, and a simple adaptation to a polluting molecule can lead to its biodegradation or biotransformation. This is the bioremediation principle which is one of the important biotechnologies who generates important results in the management of waste such as the removal of textiles dyes, which are considered to be xenobiotic compounds and recalcitrant to biodegradation. In the present bioremedial approach, a novel bacterium was isolated from dye-contaminated argan soil of the region of Souss Massa, Agadir, Morocco. Through 16S rRNA sequence matching and morphological observation it was identified as Enterobacter hormaechei. This strain has the ability to decolorize more than 100mg/L of the toxic azo dye methyl red (MR) just after 24hours of incubation. Several parameters as agitation, pH, temperature and initial dye concentrations were optimized to develop total decolorization process. The high MR decolorization ability and low nutrient requirement of this bacterium make it very useful in the biological treatment of industrial effluent containing azo dyes. The phytotoxicity assay with pepper seeds (Capsicum annuum) very cultivated in the region of Souss Massa, revealed that the decolorization of Methyl Red produced non toxic metabolites.