Fungal laccase mediated Remazol Brilliant Blue R (RBBR) dye decolorization and degradation

The use of dyes is inevitable in various industries, but sustainable decolorization poses significant challenges that exhibit the need for microbial mediation. The present study investigated the potential of C. unicolor laccase for degrading Remazol Brilliant Blue R (RBBR) dye. The laccase treatment resulted in 91.8% decolorization of 100 ppm and 34.8% decolorization of 600 ppm RBBR after 12 hours. Optimization through one-variable-at-a-time (OVAT) analysis revealed optimal conditions: 20 U/ml laccase concentration, pH 5 and a 10-hour treatment time. To examine the interactive effects of temperature and dye concentration on degradation, response surface methodology (RSM) with central composite design (CCD) was applied. The predicted maximum decolorization of 80% at 275 ppm RBBR concentration and 40°C closely aligned with the experimental result of 85%. UV-vis spectroscopy showed a reduction in absorbance at 591 nm, while LC-MS identified degradation products including hydroxyphenyl-containing compounds (m/z 216 and m/z 222) and sulfanilic acid derivatives. The current study contributes to the advancement of efficient, sustainable strategies for RBBR dye bioremediation that might address critical environmental concerns related to dye pollution and will further enhance the development of bioremediation technologies for industrial applications.