Figure 2. Validation of D-tagatose synthetic pathways. All reactions were performed with 20 mM lactose, 100 mM Tris-HCl (pH 8.0) at 30 °C. The information on pathway conditions is shown in Table 3. The yields of tagatose and galactitol in (A) Pathway I–Condition 1, (B) Pathway I–Condition 2, and (C) Pathway II–Condition 1 are shown. Experiments were performed in triplicates, and error bars represent the standard deviation.