Treatment of textile effluent using bacteria-immobilized graphene oxide nanocomposites: evaluation of effluent detoxification using Bellamya bengalensis

Abstract

Recent studies have reported graphene-based nanomaterials as novel scaffolds for the development of vigorous biocatalytic systems. The present study investigated polyacrylic acid-linked graphene oxide (GO)–gelatin nanocomposite for the immobilization of moderately halotolerant engineered bacterial consortium consisting of Dietzia sp., Bacillus sp. and Pseudomonas mendocina. This biocatalyst was subsequently applied for treatment of hypersaline textile effluents collected from local textile manufacturing and processing units. Effluent treatment efficiency of this biocatalyst was assessed in terms of its dye, surfactant and salt-removal abilities from collected effluents. High metabolic activity recorded in the case of immobilized bacterial cells indicated that immobilization had stimulated improved growth as well as electrolyte and pH tolerance in bacterial cells. Examination of the treated effluents suggested approximately 99% removal of COD, color (dyes), electrolytes and surfactant. Probable cyto-genotoxic potential and oxidative stress inducing the ability of both untreated and treated effluents was determined with Bellamya bengalensis (fresh water snail). Comet formation in hepatopancreatic cells of snails exposed to untreated effluent was significantly higher than in individuals exposed to treated effluents which in turn were similar to organisms treated as control. Hence, results of this study indicated efficient performance of GO-based biocatalyst in augmenting biodegradation and detoxification of textile effluent. The low cost incurred during the synthesis and application of bacteria-immobilized GO nanocomposite and its reusability potential determined herein established the process of effluent treatment reported in this study as a promising approach for commercial wastewater treatment.