Enhanced biohydrogen photoproduction by marine green algae Platymonas subcordiformis under decreased partial pressure of H2 directly consumed by alkaline fuel cell

Amarine green alga, Platymonas subcordiformis can produce hydrogen under the regulation of a proton uncoupler CCCP. In this study, alkaline hydrogen-oxide fuel cell (AFC)was used to directly deplete hydrogen to maintain a low partial hydrogen pressure in the reactor once it was produced from the algae in the photobioreactor. The hydrogen evolution kinetics in this AFC integrated processwas characterized and compared with that of the process without AFC. The results show that the duration of hydrogen evolution was prolonged significantly and the yield of H2 was improved about 2.3 times. This yield enhancement may be due to the removal of hydrogen feedback inhibition on hydrogen photo-evolution in algal cells. It is further found that sustaining the activities of hydrogenase and the photosynthetic system II (PSII) of the algae is critical for further improving H2 production from P. subcordiformis.