Abstract

A brown-rot fungus, Laetiporus sulphureus (Fr.) Murr., was isolated from Mbweni, Oyster Bay and Mtoni Mangroves Forests in Dar es Salaam, Tanzania, and the biochemical properties of its extracellular enzymes were investigated. The crude culture filtrate was concentrated by ultrafiltration. Protein content and lignocellololytic enzyme activities were measured by photometric methods. The crude enzyme extract was purified by gel chromatography and characterized by sodium docecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The fungal filtrate had maximum manganese peroxidase (MnP) of 2.5 U/mL and lignin peroxidase (LiP) of 1 U/mL, but showed no laccase (Lac) activity. The enzyme extracts were able to oxidize rhemazol brilliant blue-R (RBB-R) dye and phenol, and could remove up to 90% color from raw textile effluent in immobilized culture. The purified peroxidases showed that the MnP from S. sulphureus has a molecular weight of 48 kDA. The study elucidated the extracellular enzymes profile of facultative marine L. sulphureus and provided basic information on their potential for biological wastewater treatment systems.

Key words: Brown-rot fungi, extracellular enzymes, biodegradation, electrophoresis.