Large scale production of vanillin using an eugenol oxidase from Nocardioides sp. YR527

Abstract

Bacterial eugenol oxidases (EUGOs) entered recently the scientific spotlight as these versatile biocatalysts were reported to transform lignin degradation products into valuable platform chemicals. Here we describe the second member of the enzyme family, EUGO from Nocardioides sp. YR527 (NspEUGO) and investigated its biocatalytic potential in direct comparison with EUGO from Rhodococcus jostii RHA1. NspEUGO was found to be most active on vanillyl alcohol derivatives (up to 5.6 ± 0.3 s−1) while for eugenol the highest affinity was observed (KM: 33.1 ± 4.1 µM). For the catalyzed reactions, a high ambiguity was observed in dependency of the pH: The highest kcat of 16.0 ± 0.3 s−1 was found at pH 9.5 while the best long-term performance was detected at pH 6.0 (∼300,000 TTN). To stabilize the enzyme, immobilization on a total of 14 carrier materials was conducted and the performance was investigated in two reactor types for large scale application. This resulted in the successful production of vanillin at 1 g L−1 h−1 in a packed bed reactor.