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

Abstract

(-)-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.