The biosynthesis of furaneol in strawberry: the plant cells are not alone

Abstract

In this paper, our latest results on the biosynthesis of furaneol in strawberry (Fragaria x ananasa cv. Elsanta) cells are presented. Our group has been working on the biosynthesis in strawberry of this very important flavour molecule for the past decade [1–3] and the importance of 1,2-propanediol as a putative precursor of furaneol has been described [4]. In the present work, the methylotroph Methylobacterium extorquens (strain with CABI registration number IMI 369321), which has been isolated from strawberry (Fragaria x ananassa cv. Elsanta) callus cultures [5], was grown on a mixture of methanol (0.25% v/v) and 1,2-propanediol (0.75% v/v). The microbial biotransformation of 1,2-propanediol to 2-hydroxypropanal was studied. Both the bacterial and strawberry Alcohol Dehydrogenase (ADH) enzymatic activities were assessed to define the best substrate specificity. SDS-PAGE electrophoresis experiments showed molecular weights of 45.0 kDa and 24.6 kDa for the Alcohol Dehydrogenases of the Methylobacterium extorquens and Fragaria x ananassa respectively. Our results suggest that the bacterial enzymatic activity contributes to the generation of precursors of furaneol in strawberry.