Optimization of Photosynthetic Hydrogen Yield From Platinized Photosystem I Complexes

Fractional factorial design was utilized to optimize light-dependent hydrogen production by platinized Photosystem I isolated from the cyanobacterium Thermosynechoccocus elongatus BP-1 using response surface methodology (RSM).  Using JMP, statistical data analysis software, a model equation was developed to predict an optimum for hydrogen evolved, after platinization, under the optimal conditions for temperature, light intensity and platinum salt concentration.  The total H₂ yield had a significant dependence on platinum salt concentration and temperature during platinization.  Light intensity during platinization had a minimal effect on the total H₂ yield.  The surface and contour plots yielding the model equation indicated that an optimal hydrogen yield would be maximized at a light intensity of 236 μE m^-2 s^-1, platinum salt concentration of 636 μM and temperature of 30.8⁰C. The predicted optimum was 8.17 µmol H₂ h^-1 mg chl^-1.  To validate the model, an experiment was performed with observed optimal conditions during platinization, yielding 8.02 µmol H₂ h^-1 mg chl^-1 during hydrogen evolution, the highest value observed in the series of experiments.