Strain of Fusarium oxysporum Isolated from Almond Hulls Produces Styrene and 7-Methyl-1,3,5-cyclooctatriene as the Principal Volatile Components

An isolated strain of Fusarium oxysporum from the hulls of Prunus dulcis (sweet almond) was found to produce relatively large quantities of the hydrocarbons styrene and two isomers of 7-methyl-1,3,5-cyclooctatriene (MCOT). Production of styrene and MCOT was reproduced on a small scale using potato dextrose agar as a growth medium and scaled up using 1 L of inoculated potato dextrose broth. The compounds were trapped as volatile organic compounds (VOCs) onto solid-phase microextraction (SPME) for small scale and Tenax for large scale and then isolated using standard high-performance liquid chromatography (HPLC) methods. Styrene was authenticated by a comparison to the retention times, fragmentation patterns, and calculated retention indices of a commercially available sample. The identity of MCOT was verified by a short chemical synthesis and a comparison of spectroscopic data to the isolated sample. A biosynthetic scheme of styrene is proposed on the basis of a (13)C-labeling study. This is the first report of MCOT isolated as a natural product.