Light-dependent hydrogen production by platinized Photosystem I isolated from the cyanobacterium Thermosynechococcus elongatus BP-1 was optimized using response surface methodology (RSM). The process parameters studied included temperature, light intensity and wavelength, and platinum salt concentration. Application of RSM generated a model that agrees well with the data for El, yield (R(2) = 0.99 and p < 0.001). Significant effects on the total H(2) yield were seen when the platinum salt concentration and temperature were varied during platinization. However, light intensity during platinization had a minimal effect on the total H(2) yield within the region studied. The values of the parameters used during the platinization that optimized the production of H(2) were light intensity of 240 mu E m(-2) s(-1), platinum salt concentration of 636 mu M and temperature of 31 degrees C. A subsequent validation experiment at the predicted conditions for optimal process yield gave the maximum H(2) yield measured in the study, which was 8.02 mu mol H(2) per mg chlorophyll. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.