Bioremediation of dye containing wastewater using an alkalophilic bacterium Nesterenkonia lacusekhoensis

Abstract

newline Textile industry occupies an important position in the Indian economy, being the second largest after agriculture, and contributes 4% to the GDP of the country. It also counts up amongst major industries, which pollute environment, due to high dye consumption. These dyes (azo) are widely used by textile industry due to stable structures, wide range of colors and resistance towards light, sweat, heat and water. These dyes are genotoxic, mutagenic and teratogenic in nature. These dyes are also recalcitrant in nature and found to escape many treatment technologies, without being properly treated. Remediation of textile wastewater involving dye removal and dealing simultaneously with problems of high pH, COD, salinity and metals is a big challenge. Conventional methods of treatment and dye removal are very expensive. Therefore, there is a need to look for alternative bioremediation methods that are low cost and eco-friendly. The present study was conducted with the above considerations in view wherein the potential of an indigenous alkaliphilic bacterium Nesterenkonia lacusekhoensis EMLA3 isolated from textile industry was explored for its dye removal and wastewater remediation capability. The objectives were defined to examine the efficacy of N. lacusekhoensis for degrading different groups of azo dyes, to study the potential and mechanism of free/immobilized microbial cells for bioremoval of two selected reactive dyes under different operational and culture conditions in batch mode, to study enzymatic biodegradation of the dyes by the microbe, to optimize operational conditions for maximum dye bioremoval and to bioremediate dye containing wastewater in dynamic mode. The alkaliphilic bacterial strain N. lacusekhoensis EMLA3 is a gram-positive bacterium, used in the study for testing its potential towards dye decolorization. Twenty five dyes were tested for removal by the bacterium at a concentration of 100 mg/L each in nutrient broth (NB). Out of these twenty-five dyes eleven showed visual....