Co-enzyme-free, enzymatic synthesis of aldehydes from renewable resources with a new and highly efficient alkene cleaving dioxygenase

Abstract

Alkene cleaving dioxygenases (ADO), which can oxidatively cleave C=C double bonds to the respective carbonyl compounds, may aid in waste stream utilization strategies by valorizing lignin-derived monomers. Here, we present 11 new ADOs and describe the characteristics of the most promising candidate MapADO from Moesziomyces aphidis. MapADO shows unprecedented reaction kinetics and a high yield without requiring co-enzymes or co-substrates other than O2. We highlight the efficiency of MapADO by preparative scale reaction in a whole cell approach from 50 mM isoeugenol to vanillin isolated in 85 % yield. Furthermore, we demonstrate that MapADO can be employed in a cascade reaction with a eugenol oxidase (ScEUGO), enabling the use of eugenol as starting material. Moreover, we show that MapADO can be used to convert ferulic acid - a major component of lignin - to vanillin via another cascade reaction employing a phenolic acid decarboxylase (PAD).