Sustainable approach for the degradation of Contrast dye Evans blue by Enterobacter cloacae strain SD4-1

Abstract

BackgroundDischarge of dye complexes through industrial effluents continues to be a never-ending problem for the environment. Several degradation techniques have been experimented with, of which utilizing biological entities for the effective degradation of these dye molecules is extensively studied and still being explored. The present study focuses on (i) isolation of bacterial strains from the contaminated agricultural lands (ii) screening the isolates for their decolourization efficiency of Evans blue dye (iii) optimization of culture parameters such as temperature, pH, concentration of dye and nitrogen source for effective decolourization (iv) analysing the effect of degradation of diazo dye Evan's blue by the selected strain using GCMS analysis. MethodsThe bacterial strains were isolated from contaminated agricultural lands in Chennai, Tamil Nadu, India. The collected samples were aseptically transferred to the laboratory and stored for further studies. The collected samples were serially diluted, and the colonies with distinct morphology were pure-cultured. The isolated strains were studied for their efficiency to decolourize the dye Evans blue dye. The strain with higher decolourization efficiency was selected and optimized for parameters such as temperature, pH, nitrogen source and concentration of dye. The degradation of dye by the isolate was analysed by GCMS. Significant FindingsThe investigation unveiled that the strain SD4-1 of Enterobacter cloacae effectively decolorizes Evans blue dye at 37°C and pH 6.0, utilizing Sodium nitrate as the nitrogen source. SD4-1 exhibited an impressive dye decolourization efficiency of approximately 75%. The comprehensive GCMS analysis verified the bacterium's capability to fully degrade the azo dye Evans blue. Consequently, this study concludes that the SD4-1 Enterobacter cloacae strain holds promising potential for the efficient biodegradation of Evan's blue dye. Its application as a highly effective biological agent in the practical removal of dyes from textile industries is envisaged. Notably, this organism demonstrates superior performance in comparison to other studies where a mixture of dyes or consortia of microorganisms were employed for dye decolourization.