Characteristics and dyes biodegradation potential of crude lignolytic enzymes from white-rot fungus crepidotus variabilis isolated in coastal Tanzania

Abstract

Lignocellulosic enzymes from Crepidotus variabilis collected from mangrove forests of coastal Tanzania were investigated by using standard methods, and their ability to degrade aromatic compounds were elucidated. The fungal crude enzyme filtrates had maximum laccase (Lac), lignin peroxidase (LiP) and manganese peroxidase (MnP) activities of 70 U/mL, 16 U/mL and 8, U/mL respectively. The crude enzyme extracts were able to oxidize rhemazol brilliant blue-R (RBB-R) dye, phenol, "-naphthol and pyrogallol. Also, they could remove up to 58% and 92% color from raw textile effluent and aromatic dyes, respectively, after 14 days of incubation at 30ºC and pH 4.5. Desalted and size-separated enzyme filtrates, resolved by sodium docecyl sulphatepolyacrylamide gel electrophoresis (SDS-PAGE) and isoelectric focusing (IEF), showed laccases and peroxidases from C. variabilis to have molecular weights of 67 kDa and 47 kDa, respectively, while the isoelectric points (pI) of laccases and peroxidases were found to lie in a range of 3.0 to 4.1. The study provided basic information on the characteristics of crude lignolytic enzymes from C. variabilis and confirmed it to be one of the potential biodegraders of aromatic compounds that could be applied in bioremediation of polluted ecosystem.