Fig. 2

Long-term oxidations of HMF (a) and FFCA (b) by AAO showing product molar percentages referred to initial substrate concentration (continuous lines) and enzyme residual activity (dashed lines). Reactions between 1.5 mM HMF or FFCA and 2.5 µM AAO were performed in 50 mM sodium phosphate, pH 6.0, at 28 °C. Oxidation rate for FDCA production in b, estimated by fitting data to equation \(\left[ {\text{FFCA}} \right]{ = }\left[ {\text{FFCA}} \right]_{ 0} e^{{ - k_{3} t}}\), is indicated at the bottom