Antimicrobial activity of a protein obtained from fruiting body of Lentinula edodes against Escherichia coli and Staphylococcus aureus

In thepresent study, a protein extracted from the fruiting body of Lentinula edodes showed growth inhibition of Escherichia coli and Staphylococcus aureus. An aqueous extract from the dry fruiting body for purification process was used. This process was carried out in three stages, isoelectric focusing, ion exchange, preparative electrophoresis. The antimicrobial activity was evaluated by diffusion disc technique. The aqueous extract reported a protein concentration of 57.4 mg l^-1 and showed bacterial inhibition zone of 0.90 and 1.10 cm for E. coli and S. aureus, respectively; the isolated protein (9.69 mg l^-1) formed bacterial inhibition zone of 2.48 cm for E. coliand 2.68 cm for S. aureus. This protein with a purification factor of 16 showed molecular weight of 87.2 kDa and specific activity of 28 cm mg^-1. The isolated protein showed 2.8 and 2.4 times higher antimicrobial inhibition zone than aqueous extract for E. coli and S. aureus respectively, and their size was almost equal to that observed with 50 mg l^-1 gentamicin.