Fig. 2

Oxidation–reduction potential (a) and H₂O₂ concentration (b) measured in situ during enzymatic saccharification of Avicel. Reactions were initially supplied with 1000 µM ascorbic acid and were run in anaerobic conditions with H₂O₂ feeding. Feed rates used: black, 0 µmol h⁻¹ H₂O₂; blue, 50 µmol h⁻¹ H₂O₂; magenta, 100 µmol h⁻¹ H₂O₂; red, 150 µmol h⁻¹ H₂O₂; green, 300 µmol h⁻¹ H₂O₂. The shaded regions represent the standard deviation. The 300 µmol h⁻¹ H₂O₂ feed resulted in a too rapid rise in H₂O₂ concentration for the electrode to be able to record the data. Accumulation of H₂O₂ could be followed up to 50 µM, which is the upper detection limit of the H₂O₂ electrode. The magenta and red arrows indicate the approximate time points where the rate of H₂O₂ accumulation in the medium started increasing for the reactions with 100 and 150 µmol h⁻¹, respectively