The lignocellulose-derived sugar solution was then utilised for CO2 reduction reactions using the TiO2|CotpyP photocatalyst (Figure ). In a typical experiment, CotpyP (50 nmol) was added to a photoreactor containing a TiO2 suspension (5 mg, P25, particle diameter ~20 nm) in 2:1 MeCN:enzyme-treated solid fraction aqueous solution (3 mL). The photoreactor was sealed with a rubber septum and purged with 100% CO2 or 20% CO2 (balanced with N2) at a flow rate of 15 mL min -1 for 15 min. The sealed and stirred photoreactor was irradiated with a solar light simulator (100 mW cm -2 , AM 1.5G, 25 °C, 600 rpm) for 24 h. The UV in the full solar spectrum is necessary to photoexcite electrons from the valence to the conduction band of TiO2. The gaseous products (H2 and CO) in the headspace (4.74 mL) were quantified by gas chromatography (GC), and HCOO -formed in the solution from glucose photooxidation was quantified by ion chromatography. and Table ). The obtained CO yields correspond to a CO2-to-CO conversion efficiencies of ~0.03% and ~0.05% at 100vol% and 20vol% CO2, respectively. The reduction of protons (from water) to H2 and CO2 to CO as well as the oxidation of glucose/cellobiose to formate are two-electron processes with an expected 1:1 stoichiometric ratio for (H2+CO):formate, which is close to the observed ratios.