Biocatalytic synthesis of vanillin by an immobilised eugenol oxidase: High biocatalyst yield by enzyme recycling

[Display omitted] •Biosynthesis of vanillin using EUGO is optimised.•The best conditions allow an organic solvent free process of 9.9 g prod L−1 h−1.•Immobilised EUGO allowed the biocatalyst to be reused up to 18 reaction cycles.•Optimised conditions increased the safety and reduced the environmental impact. Vanilla is the second most expensive spice in the world. This issue triggered the necessity to obtain its flavour compound, vanillin, by alternative methods, most of which have focused on biosynthesis since it can be labelled as “natural” and sold at higher price. In this work, a process for the enzymatic synthesis of vanillin has been optimised, not only from a process metrics point of view but also from an environmentally sustainable perspective. The maximum biocatalyst activity and stability was taken into account for the selection of the reaction conditions. Soluble and immobilised eugenol oxidase (EUGO) was tested under both reaction conditions. The optimum conditions obtained lead to an organic solvent free process reaching 9.9 g prod L−1 h−1. Moreover, the use of immobilised EUGO allowed the biocatalyst to be reused up to 18 reaction cycles, improving the biocatalyst yield more than 12-fold, thus also reducing the biocatalyst associated cost.