Encapsulated titanium dioxide nanoparticle-Escherichia coli hybrid system improves light driven hydrogen production under aerobic condition

Utilizing light energy for hydrogen production by combining nano-bio inspired photosynthetic system has received remarkable attention in renewable energy production. In this study, we applied a sodium alginate encapsulation strategy to our previously developed nano-bio hybrid system for photocatalytic hydrogen production under aerobic condition by combining the inorganic semiconductor titanium dioxide (TiO2), electron mediator methylviologen (MV2+), along with E. coli (hydrogenases) in an encapsulated system under the given light intensity of 2000 W m(-2) and its hydrogen production efficiency was studied. Under aerobic condition the encapsulated hybrid system produced hydrogen (2.4 mmol H-2/mmol glucose) 3-fold higher than the unencapsulated hybrid system (0.8 mmol H-2/mmol glucose), suggesting that encapsulation is essential to protect oxygen sensitive hydrogenase under aerobic condition. The encapsulated hybrid system was also feasible under direct sunlight for hydrogen production. Overall, this study could serve as a new strategy for biological hydrogen production under aerobic condition.