The Drimarene Blue X3LR decolourising enzyme from Funalia trogii ATCC 200800 was isolated and identified by a newly introduced procedure and named as single step isolation and identification procedure (SSIIP). Different from the previous decolourisation studies with Funalia trogii, dye decolourising enzyme was obtained by using solid-state system. The optimum pH and temperature for enzymatic decolourisation were determined as 4.0 and 50degreesC, respectively. The enzyme decolourised the dye without the use of additional peroxide and mediator. The molecular weight of enzyme was calculated as about 65 kDa with SDS-PAGE. In SDS-PAGE, the gel was stained with the substrates Drimarene Blue X3LR and guaicol instead with Commassie Blue G-250. The colourless zone obtained after staining with Drimarene Blue X3LR turned into orange colour after staining with guaicol. We concluded that this decolourising enzyme is laccase. This new single step method introduced is very simple and useful for the detection of extracellular enzymes responsible for decolourisation while determining simultaneously their molecular weight. This simple SSIIP method could be of great importance for laboratory applications and biotechnological aims in close future. (C) 2004 Elsevier Inc. All rights reserved.