PHOTO-HYDROGEN EVOLUTION BY IMMOBILIZED MARINE GREEN ALGAE PLATYMONAS SUBCORDIFORMIS
Platymonas subcordiformis was immobilized in the alginate-gel beads under the addition of 15 μmol·L~(-1)proton gradient uncoupler CCCP for H_2 evolution. Among 5 different metal cations acted as gel bead stabilizing agents, calcium alginate beads increased H_2 evolution activity by 20％ compared with the control. The optimum bead diameter for photo-hydrogen evolution is lmm. At a wide range of cell loading the hydrogen yield is stable. The optimum pH range is enlarged with a shift of 0. 5—1 pH to the acidic conditions. The optimum temperature and light intensity are 25℃and 4000lx. After hydrogen evolution, the beads washed with 2％ DMSO were re-cultured for 7 days and showed a similar photo-hydrogen evolution activity.