Fig. 6

Optimized HMF conversion using two different V367R and 8BxHMFO doses. a Reactions with 2.5 µM enzyme, and HMF/catalase re-dosage after 2 days. b Higher FDCA production by lowering the enzyme dose (to 1.25 µM), and HMF/catalase re-dosage after 4 days. FDCA yields (lines) and residual enzyme activities (dashes) are shown during HMF (6 mM concentration, plus 6 mM addition after 2 or 4 days) reactions with the V367R (black) and 8BxHMFO (red) variants, in 50 mM Tris/HCl, pH 8.0, in the presence of catalase. FDCA production was quantified by HPLC, and residual activities were measured with vanillyl alcohol, in 50 mM Tris/HCl, pH 7.5. Mean and standard deviation values from triplicate experiments are shown