D-Fagomine is an iminosugar found in nature that lowers blood glucose peak after meal and reduces fat-induced weight gain and insulin resistance. The immediate precursor of D-fagomine is accessible straightforward via D-fructose-6-phosphate aldolase catalyzed aldol addition of dihydroxyacetone to Cbz-N-3-aminopropanal (Cbz = benzyloxycarbonyl). In this work, the performance and kinetics of the abovementioned reaction catalyzed by FSA A129G variant was studied. The reaction was investigated in two reactors; batch reactor and microreactor, and kinetic parameters were estimated from the steady state experiments in the batch reactor. This enzyme has improved stability, better K-m value for Cbz-N-3-aminopropanal and lower retro-aldol activity in comparison with previously studied aldolase variants FSA A129S and A129S/A165G. Mathematical model for both reactors was developed and validated experimentally.