Simultaneous production of D-allulose and D-tagatose from lactose

The high-demand rare sugars D-tagatose and D-allulose may be produced from lactose in a combined process, though this dual conversion has not yet been demonstrated. Four enzymes from thermophilic organisms were cloned and expressed in Escherichia coli to synthesize D-tagatose and D-allulose from lactose: b-galactosidase (Geobacillus stearothermophilus), L-arabinose isomerase (G. stearothermophilus US100), D-glucose isomerase (Weizmannia coagulans) and D-allulose epimerase (Arthrobacter globiformis). A single-pot reaction mixture yielded 9.9 +/- 1.5 mg mL-1 D-allulose and 10.7 +/- 1.1 mg mL-1 D-tagatose after 24 h at 70 degrees C. Enzyme addition order did not have an impact on yields (p = 0.3527). Higher lactose concentrations resulted in higher D-tagatose concentrations (p <= 0.001) regardless of when the lactose was added, however, specific yields for D-allulose were higher without adding additional lactose during the reaction (p <= 0.001). These experiments demonstrate that a single pot synthesis of D-tagatose and Dallulose is feasible and with more optimization could be used in industrial applications. (c) 2024 Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.