A sustainable method of crystal violet dye removal using novel strain Klebsiella pneumoniae ED2

Abstract

This study aimed to identify a potent bacterium capable of degrading Crystal Violet (CV) dye, a prominent textile dye causing environmental pollution in water bodies. A bacterial strain identified by 16S rRNA sequencing as Klebsiella pneumoniae ED2 was isolated from textile industrial effluent sediment samples. The isolated bacteria exhibited non-pathogenic and non-antibiotic resistant characteristics. The preliminary decolorization experiment evinced high CV-degrading competency i.e. 92.58 % by K. pneumoniae. Optimization experiment were conducted using a central composite design (CCD) approach to optimize pH, temperature, dye concentration, and degradation time parameters. Employing response surface methodology, degradation efficiency was enhanced. The maximum decolorization of 93.65 % was achieved at 37°C with a 1 mL inoculum volume over 48 h using 200 mg/L of CV dye. Confirmation of biodegradation was accomplished through UV–visible spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, and GC-MS analysis of both the intact CV dye and its degraded products. Microbial toxicological assessments using Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and phytotoxicity studies with Vigna radiata L. significantly reduced dye toxicity post-degradation. In conclusion, the identified K. pneumoniae strain proved to be an efficient microbe for dye degradation, offering potential applications in mitigating pollution caused by industrial dyes.