Microbial transformation of a tertiary allylalcohol: regioselective isomerisation of linalool to geraniol without nerol formation

Linalool is a natural monoterpenoic allylalcohol with a tertiary alcohol group. The initial reaction of linalool degradation under anoxic conditions was studied in nitrate-limited cultures of a recently isolated denitrifying bacterium, strain 47Lol. The primary allylalcohol geraniol was detected in the stationary phase of cultures grown on linalool. Geranial and linalool appeared in the medium of geraniol-fed cultures. Nerol was not isomerised to geraniol or linalool. It was oxidised to neral, but not further degraded. These observations indicate the presence of a new enzyme reaction, a 3,1-hydroxyl-Δ1-Δ2-mutase that regioselectively isomerises linalool and geraniol.