Selective Enzymatic Synthesis of the Grapefruit Flavor (+)‐Nootkatone. Issue 4 (2nd February 2015)

• Record Type: Journal Article
• Authors: Schulz, Sebastian; Girhard, Marco; Gaßmeyer, Sarah K.; Jäger, Vera D.; Schwarze, Daniel; Vogel, Andreas; Urlacher, Vlada B.
• Is Part Of: ChemCatChem. Volume 7:Issue 4(2015:Feb.)
• Page Start: 601
• Page End: 604
• Publication Date: 2015-02-02
• Subjects: Catalysis -- Periodicals; 541.39505
• DOI: 10.1002/cctc.201402952
• Languages: English
• ISSNs: 1867-3880

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>(+)‐Nootkatone is a high‐value sesquiterpenoid known for its grapefruit‐odor impression. Its isolation from natural plant sources suffers from low yields, and chemical syntheses involve carcinogenic or hazardous compounds. Herein, a biocatalytic route for the synthesis of (+)‐nootkatone that combines two enzymes in one pot is presented. In the first step, a cytochrome P450 monooxygenase catalyzes the selective allylic hydroxylation of the sesquiterpene (+)‐valencene to the intermediate alcohol nootkatol. In the second step, nootkatol is further oxidized to (+)‐nootkatone by an alcohol dehydrogenase (ADH). The challenging task of finding a suitable cofactor regeneration system was solved by careful selection of an appropriate cosubstrate for the ADH, which works in a dual‐functional mode. After reaction optimization, involving cosolvent and cosubstrate screening, (+)‐nootkatone concentrations of up to 360 mg <sc>L</sc>⁻¹ and a space‐time yield of 18 mg <sc>L</sc>⁻¹ h⁻¹ were achieved.</p> </abstract>