Evaluation of the Antibacterial Potential of Basidiomycetes

Food spoilage caused by microbial contamination remains a significant challenge for the food industry, contributing to quality deterioration and economic losses globally. While synthetic preservatives effectively control microbial growth, concerns regarding their safety and increasing consumer preference for minimally processed and clean-label foods have encouraged the development of natural preservation strategies. Biopreservation using naturally derived antimicrobial compounds has emerged as a promising alternative for improving food stability and safety. Basidiomycetes are known to produce diverse bioactive secondary metabolites with antimicrobial properties. This study investigated the antibacterial activity of culture extracts from submerged basidiomycete cultures against food spoilage and foodborne bacteria.

Fifteen basidiomycete strains originating mainly from Greek environments and maintained in the culture collection of the Laboratory of General and Agricultural Microbiology (LGAM) were cultivated in Yeast Peptone Glucose medium at 25 °C and 110 rpm for 30 days. After cultivation, cultures were filtered to separate biomass from culture liquid. Filtrates were subjected to liquid-liquid extraction using ethyl acetate to obtain organic and aqueous fractions. The organic phase was evaporated under reduced pressure using a rotary evaporator and reconstituted in methanol, while the aqueous fraction was tested directly. Antibacterial activity was evaluated using disk diffusion assays against different Gram positive and Gram negative bacteria, including E. coli, B. subtilis and several Pseudomonas strains.

Antibacterial activity was observed in extracts of several basidiomycetes, including Coprinus comatus that produced the largest inhibition zones. Gram negative bacteria showed lower susceptibility than Gram positive strains. These findings demonstrate that basidiomycetes produce extracellular metabolites with antibacterial potential for biopreservation applications.