Enhanced Levels of Laccase Synthesis by C. Cladosporioides and Its Potential as a Dye Decolorizing Agent

Laccases (EC 1.10.3.2) are multicopper oxidase enzymes with broad applicability in several industrial and environmental processes. In this study, laccase-producing fungi were systematically isolated from paper mill effluent samples. A total of 27 fungal isolates were obtained and identified through ITS rDNA sequencing. Among these, six isolates exhibited prominent substrate oxidation potential. The isolate GOJ7 showed the highest laccase activity, with a maximum yield of 52.00 U/mL. Molecular characterization based on ITS rRNA gene sequencing identified the isolate as Cladosporium cladosporioides. The decolorization efficiency of isolate GOJ7 was evaluated against various synthetic dyes in liquid culture. Malachite green showed the greatest decolorization at the concentration of the dye of 100 mg/L (81%), followed by methyl violet (74%), methylene blue (69%), and crystal violet (63%). Fourier Transform Infrared (FTIR) spectroscopy confirmed structural modifications in the dyes following treatment, indicating effective biodegradation. The results demonstrate that C. cladosporioides possesses strong potential as an efficient biosorbent for the remediation of dye-contaminated wastewater, offering an eco-friendly approach for reducing toxic industrial pollutants.