Fig. 3

Xylitol production by (a, c) PsXYL1 + GDH 4000–4 and (b) NcXR + GDH 4000–1 cells in multiple cylces of reactions. Symbols: (black diamond) 1st cycle, (open square) 2nd cycle, (red triange) 3rd cycle, (blue cross) 4th cycle, (pink square) 5th cycle, (green circle) 6th cycle. (a) 10 mg/mL of PsXYL1 + GDH 4000–4 cells in 50 mM KPi (pH 7.0) buffer were incubated at 30 °C with 200 mM d-xylose and 0.25 mM NAD⁺. At the end of each reaction cycle, the cells were collected by centrifugation and supernatants were removed. Fresh reaction mixture was added to the cells to start another cycle of reaction. (b) 10 mg/mL of NcXR + GDH 4000–1 cells in 50 mM KPi (pH 7.0) buffer were incubated at 30 °C with 200 mM d-xylose and 0.25 mM NAD⁺. Recycling was carried out as described above. During the 3rd cycle, 100 mM of formate and glucose were added as indicated. (c) 10 mg/mL of PsXYL1 + GDH 4000–4 cells in 50 mM KPi (pH 7.0) buffer were incubated at 30 °C with 200 mM d-xylose but without NAD⁺. NAD⁺ (0.25 mM) was added at the indicated time points (red and blue arrows) in the 3rd and 4th cycles. The data shown in the figure is the average of 3 values. All the values are within the 5% SD