Hazelnut: Explorations toward the Biocatalytic Synthesis of its Aroma Precursor

Area of Science:

• Biocatalysis and synthetic biology
• Food chemistry and flavor science

Background:

• Biocatalysis is increasingly important for industrial synthesis due to its selectivity and mild conditions.
• Filbertone is the key flavor compound in hazelnuts, but natural extraction yields variable aroma profiles.
• There is a growing demand for sustainably produced natural flavor compounds with consistent quality.

Purpose of the Study:

• To develop a novel biosynthetic pathway for the enantiomerically pure synthesis of filbertone, the principal flavor compound of hazelnut.
• To establish a multi-enzyme cascade for the sustainable production of a natural hazelnut aroma precursor.
• To address the need for reliable synthesis methods that meet regulatory claims for natural compounds in the aroma industry.

Main Methods:

• A multi-enzyme cascade was designed starting from D-Ile and L-Thr.
• Enzymatic conversion of amino acids using D-amino acid oxidase and threonine deaminase.
• Regioselective C-C ligation of intermediate carbonyl compounds catalyzed by a transketolase (TK) from Geobacillus stearothermophilus.

Main Results:

• A novel biosynthetic route for filbertone synthesis was successfully proposed.
• The pathway utilizes readily available amino acid precursors and a regioselective transketolase.
• The method allows for the production of a defined enantiomeric purity of the filbertone precursor.

Conclusions:

• The proposed multi-enzyme cascade offers a promising approach for the industrial production of natural hazelnut aroma precursor.
• This biosynthetic route provides a sustainable alternative to traditional extraction methods.
• The method supports the demand for natural compounds with consistent quality and regulatory compliance.