Analysis of volatile metabolites emitted by soil‐derived fungi using head space solid‐phase microextraction/gas chromatography/mass spectrometry: I. <i>Aspergillus fumigatus</i> , <i>Aspergillus nidulans</i> , <i>Fusarium solani</i> and <i>Penicillium paneum</i>

Abstract

The microbial volatile organic compounds (MVOCs) emitted from soil‐derived fungal strains were investigated using solid‐phase microextraction/gas chromatography/mass spectrometry. Aspergillus fumigatus (KT176 and IFM40822), Aspergillus nidulans (FGSC4), Fusarium solani (NBRC31093) and Penicillium paneum (KT138) were cultured on the Czapek‐Dox agar in various growth stages. Extracted ion chromatograms and mass spectra of MVOCs from the above fungi show that 2‐ethyl‐1‐hexanol and 2‐undecanone observed in the specimens began to increase at an early stage of incubation. Therefore, 2‐ethyl‐1‐hexanol and 2‐undecanone are candidates for indicating fungal growth if these compounds are not already present in the existing environment. Alcohols, aldehydes and ketones were found as MVOCs in most A. fumigatus , A. nidulans , F. solani and P. paneum . On the other hand, sesquiterpenes were found in only specific fungi. Because each fungal strain had a characteristic compound (sesquiterpene), these compounds are useful in identifying their fungi.As the number of spores increased with the fungal cultivation period, it was found that the amount of these MVOCs, ketones, aldehydes and alcohols also increased. Therefore, 3‐octanone is suited to be an indicator of the size of fungi (fungal amounts) because of the positive correlation found between the number of spores and the amount of the compound. On the other hand, sesquiterpenes showed a peak of MVOCs at a particular period right before spore reproduction and therefore are useful to identify both fungal species and their reproduction periods. Copyright © 2012 John Wiley &amp; Sons, Ltd.