Ultraviolet and Ethyl Methanesulfonate-Induced Mutagenesis in Aspergillus niger and Salmonella typhi for Enhanced Azoreductase Production in Azo Dyes Bioremediation

Azoreductase, an enzyme capable of degrading toxic industrial azo dyes, holds significant potential for environmental remediation. Objective: To enhance azoreductase production through innovative approaches, addressing the challenge of azo dye persistence in industrial wastewater. Method: Mutagenesis using EMS and UV irradiation was applied to Aspergillus niger and Salmonella typhi, followed by treatment with L-cysteine HCl to enhance azoreductase production. Result: Mutant strains showed significantly higher azoreductase activity and more efficient azo dye degradation than wild types. Conclusions: Mutagenesis is a promising strategy to boost azoreductase production for effective industrial dye bioremediation. Chemical mutagenesis using Ethyl Methane Sulfonate (EMS) (1–6 mM) and physical mutagenesis via UV irradiation (254 nm, 10–120 minutes) were applied to Aspergillus niger and Salmonella typhi to induce mutations. Further enhancement of enzyme production and strain resistance was achieved through treatment with L-cysteine HCl monohydrate. Comparative analysis using spectrophotometry and Fourier Transform Infrared (FTIR) spectroscopy demonstrated increase in azoreductase activity in mutant strains compared to wild strains. Additionally, textile dye degradation tests validated the enzyme’s efficacy for bioremediation.