Salic A., Ivankovic M., Ferk E., Stuparic M., Tisma M., Zelic B., 2012, Development of NAD+ Regeneration Process in Microreactors of Different Materials, Chemical Engineering Transactions, 27, 193-198.
Coenzyme NAD+ (nicotinamide adenine dinucleotide) is used in numerous biocatalytic oxidation reactions where NAD+ is reduced to NADH (reduced form of nicotinamide adenine dinucleotide). As the price of coenzyme NAD+ is extremely high, it is essential to regenerate the reduced form of coenzyme back into the oxidized form. In this study regeneration of coenzyme NAD+ was carried out by reversible oxidation of ethanol to acetaldehyde using different biocatalysts and microreactors of different materials. Based on experimental results, by measuring dependence of the reaction rate on the concentration of all components of the reaction system, kinetics of coenzyme regeneration was estimated and the mathematical model of the process was developed. The enzyme kinetics was modeled as a pseudo-homogeneous process with the double substrate Michaelis–Menten rate expression. Validation of developed mathematical model of the process was carried out on a series of independent experiments. Based on results and good agreement between model predictions and experimental results, obtained model simulation results could be used for further process optimization and development of new microreactors. Additionally, comparison of NAD+ coenzyme regeneration within a microreactor and in a batch reactor using immobilized enzyme and enzyme suspension was made. The best results were noticed when glass microreactor with suspended ADH was used (X = 95.89 %; t = 2 s).
