engleski

Mathematical modelling of the NADH oxidation catalyzed by new NADH oxidase from Lactobacillus brevis in the continuously operated enzyme membrane reactor

NADH oxidase from Lactobacillus brevis was kinetically characterized in two different buffers: Tris HCl and glycine-sodium pyrophosphate pH 9.0. Reaction kinetics was described by Michaelis-Menten model with product, NAD+, inhibition. It was found that the type of this inhibition is uncompetitive. Experiments in the continuously operated enzyme membrane reactor revealed high enzyme deactivation at two different residence times: 12 and 60 min. Higher deactivation was noticed at the lower residence time in glycine-sodium pyrophosphate buffer. Enzyme deactivation was assumed to be of the first order. The developed mathematical model for the continuously operated enzyme membrane reactor described these experiments quite well. Mathematical model simulations revealed that high enzyme concentration (up to 30 g cm-3) is necessary to obtain and keep the stationary NADH conversion near 100 % through the longer period of time.

NADH oxidase ; coenzyme regeneration ; enzyme kinetics ; enzyme membrane reactor ; inhibition

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