Solar hydrogen-producing bionanodevice outperforms natural photosynthesis

Area of Science:

• Bio-nanotechnology
• Photosynthesis research
• Renewable energy

Background:

• Oxygenic photosynthesis sets a high benchmark for electron transfer rates.
• Existing solar biohydrogen systems often struggle to match this efficiency.
• Photosystem I (PSI) is a key component in many biohydrogen production strategies.

Purpose of the Study:

• To engineer a biological/organic nanoconstruct for enhanced solar biohydrogen production.
• To directly link Photosystem I (PSI) with a hydrogenase enzyme.
• To overcome electron transfer limitations in artificial photosynthetic systems.

Main Methods:

• Optimized a nanoconstruct by directly tethering the F(B) cluster of PSI to the [FeFe]-hydrogenase.
• Utilized PSI from Synechococcus sp. PCC 7002 and hydrogenase from Clostridium acetobutylicum.
• Measured hydrogen (H(2)) evolution rates under illumination.

Main Results:

• The PSI-[FeFe]-hydrogenase nanoconstruct achieved H(2) evolution at 2,200 ± 460 μmol mg chlorophyll(-1) h(-1).
• This rate is equivalent to 105 ± 22 electrons per PSI per second.
• This electron throughput is more than double that of in vivo oxygenic photosynthesis (47 e(-)PSI(-1) s(-1)).

Conclusions:

• Directly tethering redox cofactors in a bio-hybrid system overcomes diffusion limitations.
• This approach significantly enhances electron transfer rates for solar biohydrogen production.
• The engineered nanoconstruct demonstrates a viable strategy for surpassing natural photosynthetic efficiency.