Shiitake mushroom is the Japanese common name for the genus Lentinula edodes, and Shiitake is a fungus of medicinal and industrial importance. The enzyme Mannanase was purified from the fungal culture filtrate. It included a series of steps, including precipitation with ammonium sulfate and a saturation rate of 80%, in which the specific activity reached 2 units/mg, and the enzymatic accumulation was 80%. It was followed by enzyme dialysis for a whole day, which caused an increase in the specific activity to 3 units/mg, the number of purification times reached 3 times, and the enzymatic accumulation reached 71%. It is noticed from the ion exchange step using DEAE-cellulose that the specific activity increased to 10 units/mg, the number of purification times reached 10 times, and the enzymatic accumulation reached 53%. Subsequently, the last purification step was carried out using gel filtration chromatography Sephadex G-150, in which the specific activity of the enzyme reached 24 units/mg and the number of purification times reached 24 times, with an enzymatic accumulation of 48%. The molecular weight was determined using electrophoresis in a polyacrylamide gel, and its molecular weight was 58 kilodaltons. The optimum pH for its activity was 6.5, while the pH ranged between (5.5-7) to prove its activity. The optimum temperature for enzyme activity was 60°C, while the thermal stability was between (20-80) °C. Keywords: Lentinula edodes, β-mannanase activity, purifi-cation, DEAE-Sephadex A-150, Characterization, removing and ability of detergents to clean clothes.