Optimization of a photoregeneration system for NADH using pristine TiO2 as a catalyst

•NADH was regenerated with high yield up to 90% via UV photocatalysis using pristine TiO2 as the catalyst.•EDTA as the electron donor is superior to TEOA, CH3OH, NTA-3Na and H2O.•The reaction is sensitive to pH value, the concentrations of electron donor and rhodium mediator.•Regenerative NADH shows almost identical biological activity to fresh that.