Development of a synthesis method for odor sesquiterpenoid, (−)-rotundone, using non-heme Fe²⁺-chelate catalyst and ferric-chelate reductase

(−)-Rotundone, a sesquiterpenoid that has a characteristic woody and peppery odor, is a key aroma component of spicy foodstuffs, such as black pepper and Australian Shiraz wine. (−)-Rotundone shows the lowest level of odor threshold in natural compounds and remarkably improves the quality of various fruit flavors. To develop a method for the synthesis of (−)-rotundone, we focused on non-heme Fe²⁺-chelates, which are biomimetic catalysts of the active center of oxygenases and enzymatic supply and regeneration of those catalysts. That is, we constructed a unique combination system composed of the oxidative synthesis of (−)-rotundone using the non-heme Fe²⁺-chelate catalyst, Fe(II)-EDTA, and the enzymatic supply and regeneration of Fe²⁺-chelate by ferric-chelate reductase, YqjH, from Escherichia coli. In addition, we improved the yield of (−)- rotundone by the application of cyclodextrin and glucose dehydrogenase to this system, and thus established a platform for efficient (−)-rotundone production.