Objective: To identify an endophytic fungus BLH34 isolated from the leaf of Macleaya cordata with antibacterial activity,and to optimize its fermentation medium.
Methods: Antimicrobial activity of an endophytic fungus BLH34 was determined by the cylinder plate method. The morphological characteristics and internal transcribed spacer（ ITS） sequence were analyzed to identify the taxonomic position of the strain BLH34. The culture medium recipe was optimized by single factor and orthogonal experiment.
Results: The results showed that the strain BLH34 had antimicrobial activity to the test strains,especially it showed significant inhibitory effect on Staphylococcus aureus. The strain BLH34 was identified as Penicillium turbatum,and the best culture medium recipe could be recognized as follows: 5% soluble starch,4% peptone,0. 06% NaNO3,and 0. 012% MgSO4·7H2O.
Conclusion: The antimicrobial activity of crude extract was significantly increased after optimization, which could provide a basis for further separation and purification of the antibacterial substances extracted from strain BLH34.