A SIMPLE METHOD FOR COLLECTION OF VOLATILE METABOLITES FROM FUNGI BASED ON DIFFUSIVE SAMPLING FROM PETRI DISHES

A simple method for collection of volatiles from fungi cultivated in Petri dishes has been developed. Volatiles were collected by diffusive sampling onto tubes containing either carbon black or Tenax TA. The method was used to collect and compare profiles of volatiles produced on Czapek yeast autolysate agar (CYA) of two taxonomically closely related species, Penicillium clavigerum and Penicillium vulpinum. P. clavigerum mainly produced geosmin which is responsible for its typical mouldy odor, whilst P. vulpinum produced a number of different unsaturated compounds e.g. mono- and sesquiterpenes. The two species could therefore easily be distinguished on the basis of their volatile profiles. The pea-like odor of P. vulpinum was due to production of two methoxy-pyrazines. Statistical treatment of quantitative data on the 24 major volatiles collected from five isolates of P. vulpinum made it possible to distinguish between isolates. Thus our results indicate that volatile fungal metabolites can be used in chemotaxonomic studies of fungi when they are cultured under controlled conditions. Because diffusive sampling is non-destructive a major advantage of this method is that it can be applied together with traditional methods for studying fungal growth and metabolism.