Menth-1-ene

The biotransformation of linalool by Botrytis cinerea has also been described [60]. After addition of linalool to botrytised must, a series of transformation products was identified (E)- (49) and (Z)-2,6-dimethyl-2,7-octadiene-l,6-diol (48), trans- (76) and cw-furanoid linalool oxide (77), trans- (78) and c/s-pyranoid linalool oxide (79) and their acetates (80, 81), 3,9-epoxy-p-menth-1 -ene (75) and 2-methyl-2-vinyltetrahydrofuran-5-one (66) (unsaturated lactone), Fig. (11). Quantitative analysis however, showed that linalool was predominantly (> 90%) metabolised to ( )-2,6-dimethyl-2,7-octadiene-l,6-diol (49) by B. cinerea. The other compounds were only found as by-products in minor concentrations. 

As mentioned before, a Pseudomonas incognita was isolated by enrichment technique on the monoterpene alcohol linalool that was also able to grow on geraniol, nerol and limonene [36]. The metabolism of limonene by this bacterium was also investigated [37]. After fermentation the medium yielded as main product a crystallic acid, perillic acid, together with unmetabolised limonene, and some oxygenated compounds dihydrocarvone, carvone, carveol, p-menth-8-en-1 -ol-2-one, p-menth-8-ene-1,2-diol or p-menth-1 -ene-6,9-diol (structure not fully elucidated) and finally / -isopropenyl pimelic acid. 

Figure 4. Structures of terpenoids formed from linalool (1) by Botrytis cinerea. (19)>(20) (E)- and (Z)-2,6-dimethyl-2,7-octadie-ne-l,6-diol (21),(22) (Z)- and (E)-linalool oxides, furanoid (23),(24) (Z)- and (E)-linalool oxides, pyranoid (25),(26) (Z)-and (E)-linalool oxide acetates, pyranoid (27) 3,9-epoxy-p-menth-1-ene (28) 2-vinyl-2-methyl-tetrahydrofuran-5-one.

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