RESUMEN
Ganoderma lucidum belongs to Ganodermataceae family and is a famous medicinal fungus with medicinal properties like antidiabetic, antihypertension, immunomodulating, antiviral and antibacterial effects. Due to its great medicinal effect and lack of investigation on Iranian species, this study was performed. In this study, we have investigated antibacterial activity of aqueous extract at four concentrations [50, 125, 250, 500 mg ml [-1]] against 3 standard Gram positive bacteria [Bacillus subtilits, Staphylococcus aureus, Entrococcus fecalis] and 2 standard Gram negative bacteria [Pseudomonas aeroginosa and Escherichia coli] by using Disk diffusion method. Total polysaccharide of the aqueous extract and sugar composition were analyzed by phenol sulfuric acid method and GC/MS, respectively. The results indicated that the aqueous extract had antibacterial effect against Pseudomonas aeroginosa at concentration of 500 mg ml[-1]. The polysaccharide content was 37.751 mg g[-1] and the monosaccharide's constituents were identified. Based on this finding the fungus contains a great amount of polysaccharides that can be use for medicinal properties, but it is not recommended for antibacterial usage according to its weak inhibitory activity