title: Mathematical modelling of NADH oxidation catalyzed by new NADH oxidase from Lactobacillus brevis in continuously operated enzyme membrane reactor.
abstract: 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 using the Michaelis-Menten model with product (NAD(+)) inhibition. It was found that this type of inhibition is uncompetitive. Experiments in the continuously operated enzyme membrane reactor revealed a strong enzyme deactivation at two different residence times: 12 and 60 min. A stronger deactivation was observed at the lower residence time in the 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 very well. The mathematical model simulations revealed that a high enzyme concentration (up to 30 g cm(-3)) is necessary to obtain and maintain the stationary NADH conversion near 100% for a longer period of time.
authors.affiliation: Faculty of Chemical Engineering and Technology, University of Zagreb, Savska c. 16, HR-10 000 Zagreb, Croatia.
authors.forename: Zvjezdana
authors.initials: Z
authors.lastname: Findrik
authors.forename: Ana
authors.initials: A
authors.lastname: Vrsalović Presecki
authors.forename: Durda
authors.initials: D
authors.lastname: Vasić-Racki
mesh_terms: D019149:Bioreactors / Q000382:microbiology*; D003198:Computer Simulation; D052196:Levilactobacillus brevis / Q000378:metabolism*; D008567:Membranes, Artificial; D008954:Models, Biological; D009097:Multienzyme Complexes / Q000378:metabolism*; D009243:NAD / Q000378:metabolism*; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism*; D010084:Oxidation-Reduction
chemical_list: D008567:Membranes, Artificial; D009097:Multienzyme Complexes; D009243:NAD; C023107:NADH oxidase; D009247:NADH, NADPH Oxidoreductases