Decolorization of two azo dyes using marine Lysobacter sp. T312D9

Aims: Novel azo dye-degrading bacterium T312D9 strain has been isolated from Abou Quir Gulf, Alexandria, Egypt. Methodology and Results: The identification of the isolate by 16S rRNA gene sequencing revealed to be Lysobacter sp. This marine ecofriendly isolate was exploited for its ability to degrade two synthetic azo dyes considered as detrimental pollutants from industrial effluents: congo red and methyl red. Using different dye concentrations showed the highest metabolic activity for complete degradation obtained from 100 to 500 mg/L within 30 h under static condition, also, sustaining higher dye loading of 1 g/L was carried out. The significant induction of enzymes NADH - 2,6-dichloroindophenol (NADH-DCIP) reductase and tyrosinase indicated their prominent role in dye degradation. The biodegradation of two azo dyes were analyzed by gas chromatographic-mass spectrum analysis (GC-MS) and Fourier transform infrared spectroscopy (FTIR) before and after treatment. Toxicity study revealed the much less toxic nature of the metabolites produced after complete decolorization. Conclusion, significance and impact of study: Lysobacter sp T312D9 represent an inexpensive and promising marine bacteria for removal of both methyl and congo red. High sustainable metabolic activity for biodegradation under static condition. NADH-DCIP reductase and tyrosinase were significantly induced during biodegradation of dyes. The obtained metabolites revealed to be less toxic in nature which offers a practical biological treatment.