Synergistic plant-microbial biocatalytic system for enhanced degradation of toxic azo dyes

Textile effluents are a major contributor to environmental contamination due to the extensive discharge of persistent azo dyes. Eriochrome black and Methyl orange, widely used in textile processes, exhibit high chemical stability and toxicity, necessitating their effective removal to prevent adverse ecological impacts. In this study, dye resistant bacterial strains ( Burkholderia sp. and Stenotrophomonas maltophilia ) were isolated and combined with selected plants species ( E. crassipes , P. stratiotes , A. filiculoides , and H. verticillate ) to treat dye-contaminated samples. The integrated plant-bacteria treatment demonstrated superior performance, achieving 71% dye degradation, pH 7.3, BOD 63 mg/L, COD 116 mg/L, TDS 2118 mg/L, along with enhanced plant growth parameters (root length 5.02 cm, shoot length 7.266 cm, fresh weight 0.302 g, dry weight 0.023 g, protein content 8.02 μg/g, malondialdehyde 1.03µmol/g, chlorophyll a 0.24 mg/L and chlorophyll b 1.13 mg/L). Overall, Stenotrophomonas maltophilia and H. verticillate exhibited higher remediation efficiency compared to Burkholderia sp. and other tested plant species ( P. stratiotes, A. filiculoides, and E. crassipes ) for the degradation of Eriochrome Black dye and Methyl Orange. These findings confirm that plant-microbe interaction offers a promising, eco-friendly and sustainable strategy for the bioremediation of azo dye pollution.