Title : Enzymatic and functional characterization of synthetic dye biotransformation by a pre-isolated bacterial strain
Abstract:
The indiscriminate release of synthetic dyes from textile effluents poses a serious threat to aquatic ecosystems and public health. Addressing this challenge, the present dissertation investigates the bioremediation potential of a bacterial isolate through a comprehensive, multi-method approach encompassing liquid broth degradation, solid agar-flat decolorization, and laccase enzyme activity assessment using the ABTS assay.
In the liquid broth assay, two inoculum regimes (5 µL and 2.5 µL) were tested in nutrient-rich media across varied dye concentrations. Dye degradation was quantified spectrophotometrically following centrifugation and collection of the cell-free supernatant. Notably, enhanced degradation efficiency was observed at lower dye concentrations, with the 5 µL-inoculated set demonstrating faster and more consistent decolorization within 72 hours.
Parallel agar-flat assays, involving dye incorporation into solidified media followed by surface inoculation, provided a visual understanding of degradation kinetics. Decolorization zones were evident from 2.5 ppm to 15 ppm within 7–10 days, while 20 ppm required extended incubation, highlighting concentration-dependent efficacy.
To elucidate the enzymatic mechanism, extracellular laccase activity was confirmed using the ABTS–phosphate buffer method. The culture supernatant exhibited measurable activity, peaking between Day 2 and Day 3, suggesting inducible oxidative enzyme production under dye stress.
Collectively, these findings establish the isolate’s capacity for effective dye biodegradation, supported by laccase-mediated mechanisms. This work not only underscores the isolate’s environmental relevance but also contributes foundational insight for its deployment in green, low-cost wastewater treatment technologies.
Keywords: Bioremediation, Laccase, Dye Decolorization, ABTS Assay, Bacterial Isolate, Textile Effluents, Wastewater Treatment.
