CHARACTERIZATION OF VOLATILE METABOLITES FROM 47 PENICILLIUM-TAXA

Forty-seven different taxa within Penicillium were investigated for th e production of volatile metabolites. Fungi were cultured on three aga r media in Petri dishes. Volatiles were collected by diffusive samplin g onto tubes with carbon black for 2 wk, and then extracted with dieth ylether. Ether extracts were analysed by gas chromatography (GC) and v olatiles were characterized by mass spectrometry (MS) and Fourier tran sform infrared spectroscopy (FTIR). Their retention indices (RI) were compared with those of authentic compounds. In total, 196 different vo latile metabolites were characterized from the taxa investigated. Abou t 70 metabolites were assigned by MS as isomeric sesquiterpene hydroca rbons (C15H24), such as beta-caryophyllene,alpha-bergamotene and thujo psene. However, the majority of sesquiterpenes have only been characte rized by RI and mass spectral data generated at 70 eV, in a 9 peak ind ex Computer matching of spectral data with spectra in the NIST library showed that these compounds could not be assigned. A number of monote rpenes, alcohols, esters, ketones, alkenes and a few aromatic compound s were also produced. Geosmin and 2-methyl-isoborneol, reported as con tributing to mouldy/earthy off flavours, were both produced by a numbe r of different taxa, reported here for the first time. More than half of the metabolites were only detected from one species and nearly all taxa each produced a unique profile of volatile metabolites. Thus, the present study has demonstrated the potential of species of Penicilliu m as producers of a great diversity of volatile metabolites, likely to be useful in chemosystematics.