Solar hydrogen-producing bionanodevice outperforms natural photosynthesis

摘要

Although a number of solar biohydrogen systems employing photo-system I (PSI) have been developed, few attain the electron transfer throughput of oxygenic photosynthesis. We have optimized a biological/organic nanoconstruct that directly tethers F_B, the terminal [4Fe-4S] cluster of PSI from Synechococcus sp. PCC 7002, to the distal [4Fe-4S] cluster of the [FeFe]-hydrogenase (H_2ase) from Clostridium acetobutylicum. On illumination, the PSI-[FeFe]-H_2ase nanoconstruct evolves H_2 at a rate of 2,200 ± 460μmol mg chlorophyll~(-1) h~(-1), which is equivalent to 105 ± 22 e~-PSI~(-1) s~(-1). yanobacteria evolve O_2 at a rate of approximately 400 μmol mg chlorophyll~(-1) h~(-1), which is equivalent to 47 e~-PSI~(-1) s~(-1), given a PSI to photosystem II ratio of 1.8. The greater than twofold electron throughput by this hybrid biological/organic nanoconstruct over in vivo oxygenic photosynthesis validates the concept of tethering proteins through their redox cofactors to overcome diffusion-based rate limitations on electron transfer.