This study systematically investigated the decolorization efficacy and detoxification effect of crude laccase derived from Pleurotus ostreatus yang1 on azo and triphenylmethane dyes. This research encompassed decolorization efficiencies for 15 dyes (7 azo dyes and 8 triphenylmethane dyes), time course decolorization kinetics, and detoxification assessment using rice (Oryza sativa) and wheat (Triticum aestivum) seed germination as phytotoxicity indicators for both single-dye and mixed-dye systems. Molecular docking was employed to elucidate the laccase-dye interaction mechanisms. The results demonstrated that crude laccase from Pleurotus ostreatus yang1 exhibited significant decolorization efficiency and effective detoxification capacity toward both azo dyes and triphenylmethane dyes. It also displayed considerable decolorization efficiency for mixtures of azo and triphenylmethane dyes (mixture of two types of dyes), along with strong detoxification capability against the phytotoxicity of mixed dyes. Crude laccase showed robust continuous batch decolorization capability for azo dyes Alpha-naphthol Orange (α-NO) and Mordant Blue 13 (MB13). Similarly, it achieved high continuous batch decolorization efficiency for triphenylmethane dyes (e.g., Cresol Red, Acid Green 50) while maintaining stable laccase activity throughout the decolorization process. Crude laccase demonstrated excellent reusability and sustainable degradation performance during the continuous batch decolorization. The decolorization of crude laccase could significantly reduce or completely eliminate the phytotoxicity of both single dyes and mixtures of two dyes (pairwise mixtures of different types of dyes, totaling 18 different combinations). The results of molecular docking between the laccase protein and structurally diverse dyes further elucidated the underlying causes and potential mechanisms for variations in the catalytic ability of laccase toward different structural dyes. In summary, crude laccase from Pleurotus ostreatus yang1 possessed great application value and potential for efficiently degrading and detoxifying dye pollutants of different structural types.
Keywords: Pleurotus ostreatus; azo dye; decolorization; detoxification; laccase; molecular docking; triphenylmethane dye.