(+)-Nootkatone, ethyl (R)-3-hydroxyhexanoate and (-)-rotundone are included in some fruits and spices in nature, and one of the most valuable compounds in flavor and fragrance industry.  These compounds are synthesized by chemical oxidation methods so far, however, which can produce the mixture of regio- and/or enantiomeric isomers with different sensory properties.  And the requirement of subsequent purification steps invokes low recovery rates and high production costs.  

Therefore, the biotechnological processes which can overcome these problems could be the powerful tool and expected as a promising alternative.  Under these backgrounds, we focused on microbial P450 monooxygenases which are widely distributed across species and participate in various oxidation steps of natural products in metabolic pathway.  Screening P450 monooxygenase gene library that we previously constructed, we successfully obtained the P450s which possess the oxidative abilities of α-guaiene to (-)-rotundone.  This is the first report of (-)-rotundone synthesis by microbial P450 monooxygenases, and this result has the potentiality to develop industrial methods for (-)-rotundone production.  Furthermore, this method can apply to the selective synthesis of other flavor compounds, and which leads to the construction of industrially advantageous processes.