C15H24 VOLATILE COMPOUNDS UNIQUE TO AFLATOXIGENIC STRAINS OF ASPERGILLUS-FLAVUS

Headspace volatiles from eight strains of Aspergillus flavus (four afl atoxigenic strains and four nonaflatoxigenic strains), grown for 1, 2, 3, 4, 8, and 10 days in submerged cultures, were collected in Tenax G C traps. The traps were desorbed onto a 50-m gas-liquid chromatography capillary column by heat and gas purge from an external direct inject or device. The column was interfaced with a mass spectrometer data acq uisition system. Peaks were identified by comparing retention times an d mass spectra with those obtained from authentic compounds and by usi ng a computer-assisted mass spectral data base. Aflatoxigenic strains of A. flavus produced several C15H24 compounds (e.g., alpha-gurjunene, trans-caryophyllene, and cadinene) which peaked in 3-day cultures and were not present in earlier (1- and 2-day) or later (8- and 10-day) c ultures. None of these volatiles were detected in nonaflatoxigenic str ains of A. flavus. There was an apparent correlation between the relea se of C15H24 volatile compounds and the initiation of aflatoxin biosyn thesis, and a correlation between decline of aflatoxin synthesis and t he disappearance of the C15H24 compounds unique to aflatoxigenic A. fl avus also existed.