Determination of microbial volatile organic compounds from Staphylococcus pasteuri against Tuber borchii using solid-phase microextraction and gas chromatography/ion trap mass spectrometry

The mycelium of Tuber borchii Vittad., a commercial truffle species, is used as a model system for in vitro ectomycorrhizal synthesis, infected seedling production and biotechnological applications. Our fungal cultures were accidentally contaminated with a Staphylococcus pasteuri strain, showing a strong antifungal activity against T. borchii mycelium. In order to identify the antifungal volatile agents produced by S. pasteuri, solid-phase microextraction (SPME) with gas chromatography and mass spectrometry (GC/MS) was used. Using this method 65 microbial volatile organic compounds (MVOCs), synthesized by this bacterium in either single or in fungal-bacterial dual culture, were identified. SPME combined with GC/MS may be a useful method for the determination of MVOCs involved in the antifungal activity. These results showed that bacteria with unusual biological activities could be a major problem during large-scale production of inoculum for truffle-infected seedling.