Why Hydrogen? Highest energy/mass density of all known fuel types Produced Domestically Sustainable (if produced from water) Environmentally Friendly Fuel Cell: No pollutants or greenhouse gases ICE: only (NOx)
Chlamydomonas reinhardtii Single-celled green Algae 1939: German researcher Hans Gaffron discovered hydrogen metabolism Hydrogenase Catalyzed reaction, active only in absence of oxygen
Low light conversion effiency (~10%) Oxygen production inhibits Fe-hydrogenase Has not yet been overcome after 60 years of research
Coordinated photosynthetic and respiratory electron transport and coupled phosphorylation during H2 production.
Regulation of Hydrogenase Grown under photo-autotrphopic condions algae neither consume or produce hydrogen Fe hydrogenase gene induced upon incubation of cells under anaerobic conditions in the dark, or S deprivation Results suggest oxygen is a positive suppresser of Fe hydrogenase gene expression at transcriptional level
Possible Solutions to Current Limitations Low light conversion efficiency: Truncate chlorophyll antenna size of PS-II using RNAi method Availability of reduced Ferrodoxin for Fe-Hydrogenase: Change Ferrodoxin affinity for (FNR) without affecting Fe-hydrogenase interaction