acib - Austrian Centre of Industrial Biotechnology
Vanillin is in high demand and is required for many applications. In the last decades its synthetic production largely relied on the petrol-chemical feedstock guaiacol. However, with the global call to exploit bio-based renewables, vanillin producers seek for novel and sustainable biosynthetic processes. We step 150 years back, when manufacturing of this already popular aroma was based on eugenol, the major component of clove oil. We revisited this simple – yet hazardous – synthetic route via isomerization and C=C cleavage to design a 2-step cascade requiring biocatalysts only. The double bond of eugenol was formally isomerized to get in conjugation to the aromatic ring, by oxidation to coniferyl alcohol with eugenol oxidase from Rhodococcus jostii (EUGO). Then, the C=C could be potentially cleaved in an oxidative fashion to obtain vanillin and glycolaldehyde as by-product. For this purpose, we screened putative and characterized alkene cleavage oxygenases (COs), 28 in total, among the carotenoid dioxygenase protein family for activity towards coniferyl alcohol. Finally, the combination of RjEUGO and the alkene cleavage oxygenase from Sphingomonadales bacterium in a one-pot-one-step reaction led the bioproduction of vanillin from both eugenol as well as crude clove oil with comparable conversion. This new biocatalytic strategy enables to green synthetic processes, but also raises the value of the final product, which can be classified as natural when starting from natural eugenol.
Acknowledgments: The COMET center: acib: Next Generation Bioproduction is funded by BMK, BMAW, SFG, Standortagentur Tirol, Government of Lower Austria und Vienna Business Agency in the framework of COMET – Competence Centers for Excellent Technologies. The COMET-Funding Program is managed by the Austrian Research Promotion Agency FFG.
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Wed. April 17 | 09:50 – 10:10 hrs – Biosynthesis of vanillin from clove oil: a new enzymatic cascade to reconvert a past synthetic process