We conceived an integrative artificial photosynthesis platform, Solar Hunter, in which engineered strains, living biofilms and biofilms-interfaced semiconductor nanomaterials reside in harmony, carefully divide individuals' labor and synergistically work towards value-added products.
Integrative Biohydrogen System
We proposed and demonstrated a sun-powered biofilm-interfaced artificial hydrogen-producing system, Solar Hunter, that harnesses the energy from sun light. Biofilm-anchored nanorods can efficiently convert photons to electrons, which seamlessly tap into the electron chain of engineered strain carrying FeFe hydrogenase gene cluster, thereby achieving high-efficiency hydrogen production. Furthermore, the intrinsic adherence of biofilms towards various interfaces allows us to grow biofilms on easy-separation micro-beads, therefore facilitating recyclable usage of the biofilm-anchored NRs and endowing this whole system with recyclability.
Nanomaterials are those nanoscale objects serving as solar energy harvester. When firmly anchored onto E. coli biofilms through coordination chemistry, they can be easily recycled together with scalable biofilm coatings and still possess the capability to efficiently convert photons into electrons upon light exposure. The acquired electrons would tap into the electron chains of engineered strain harboring hydrogenase gene cluster, thereby fulfilling hydrogen production.
Biofilms function as a platform to sustain the whole system. Biofilms can immobilize NRs firmly so that they prevent potential damage and stresses caused by free NRs, as is the case in traditional artificial photosynthesis system. In addition, 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.
