Antibacterial effect of the culture fluid of Lentinus edodes mycelium grown in submerged liquid culture.

The antimicrobial activity of the culture fluid of Lentinus edodes mycelium grown in submerged liquid culture was tested against some common bacterial species and Candida albicans. The mycelium-free culture fluid was bacteriostatic against Streptococcus pyogenes, Staphylococcus aureus and Bacillus megaterium. The substance responsible for the activity was heat-stable, could be extracted with chloroform and had a molecular weight under 10000. These characteristics suggested that the component might be lenthionine, an antibacterial and antifungal sulphur-containing compound. The culture fluid was less toxic to human tissue culture cells than to microbes. The antibacterial activity and toxicity could not be attributed to the same component.