Artificial photosynthesis represents a promising solution for energy issues, however, the efficiency, robustness, and scalability does not meet the requirements of industrial applications. We proposed and demonstrated a sun-powered biofilm-interfaced artificial hydrogen-producing system, Solar Hunter, that could potentially solve the issues above.
Biofilms function as a platform to sustain the whole system in vitro. Biofilm-anchored nanorods can efficiently convert photons to electrons, which transfer to engineered strain producing FeFe hydrogenase gene cluster, thereby achieving high-efficiency in biohydrogen production. In addition, a brilliant traits, the intrinsic adherence of biofilms towards various interfaces, allows us to grow biofilms on easy-separation micro-beads. Based on those merits, biofilm stand out by facilitating recyclable usage of the biofilm-anchored NRs and endowing this whole system with recyclability.
In our sun-powered biofilm-interfaced hydrogen-producing system, hydrogenase harnessed in engineered E. coli are conceived to efficiently catalyze proton reduction upon receiving electrons originally donated by semiconductor nanomaterials. Electron transportation from semiconductors to hydrogenase could be bridged and facilitated by the use of mediators, methyl viologen. To achieve efficient enzymatic activities, we codon-optimized and constructed the whole hydrogenase gene clusters (from Clostridium Acetobutylicum) by leveraging the multi-expression Acembl System.
Quantum dots (QDs) and nanorods (NRs), as semiconductor nanocrystals, are of fundamental and technical importance. Owing to their extraordinary optical properties and high quantum-yield efficiency, these nanoobjects are often geared towards many energy-relevant applications. In our IGEM project, we conceive to harness those nanoscale objects as solar energy harvester. When firmly anchored onto E. coli biofilms through coordination chemistry, they can be easily recycled together with scalable biofilm coatings when necessary, and meanwhile, still possess the capability to efficiently convert photons into electrons upon light exposure. The aquired electrons would then tap into the electron chains of engineered strain harboring hydrogenase gene cluster, thereby assisting the enzymes to fulfill hydrogen production.
