ADH based NAD+ regeneration in a microreactor

Abstract

AbstractBACKGROUNDThe coenzyme NAD+ (nicotinamide adenine dinucleotide) is commonly used in biocatalytic oxidations catalysed by the enzyme alcohol dehydrogenase (ADH). As the price of the coenzyme NAD+ is extremely high, it is essential to regenerate the reduced form of the coenzyme back into the oxidized form. In this work the regeneration of the coenzyme NAD+ was carried out in a microreactor by reversible oxidation of ethanol to acetaldehyde with the ADH enzyme.RESULTSA 100% conversion of NADH was achieved for a residence time of just τ = 0.8 s when the concentration of acetaldehyde was in excess (ci,NADH = 5.5 mmol dm‐3, ci,acetaldehyde = 44 mmol dm‐3, γi,ADH = 0.2 g dm‐3, 75 mmol dm‐3 glycine‐pyrophosphate buffer pH = 9; T = 25°C). A 2D mathematical model for the description and prediction of microreactor performance was developed. Model simulations were validated using data from independent experiments.CONCLUSIONThe high conversions that were obtained for short residence times mean that the microreactors can be considered as good and efficient methods for coenzyme regeneration. © 2013 Society of Chemical Industry