Reserch Institute for Photobiological Hydrogen Production -A Grand design for large-scale renewable energy production-

Nitrogenase-based Hydrogen production

Nitrogenase-based H2 Production by Cyanobacteria

N2 + 8 e- + 8 H+ + 16 ATP → H2 + 2 NH3 + 16 (ADP + Pi)

　(In the absence of N2 ) 2 e- + 2 H+ + 4 ATP →　H2 + 4 (ADP + Pi)

Cooperation of Vegetative cell and Heterocyst

Nitrogenase-based H2 Production by Cyanobacteria

Nostoc sp. PCC 7422 shown Higi N2ase activity
★Nostoc sp. PCC 7422 had the highest N2ase activity
（Yoshino　et al. 2007)

Construction of Nostoc sp. PCC 7422 ΔHupL mutant

Sequencing and disruption of the gene to create ΔHupL mutant of Nostoc sp. PCC 7422
（We thanｋ　Dr.C.P.Wolk for plasmids）

Disruption of HupL gene

White fluorescent light

90 mmol photon m-2s-1 (PAR)

Cultibation of the mutant by white fluorescent light

Accumulation of H2 to 30%

The mutant accumulate Hydrogen up to 30% of head space
Initial amount of cells(30µg Chl a)
gas volume(ml):(7,13,19)
suspension(ml):(18,12,6)
flask volume: 25ml

Energy conversion efficiency 3.7%(vs. PAR) 1.7%(vs. solar energy)

Energy conversion efficiency of the mutant reach to 1.7%

Improvement of nitrogenase

(Air) N2 + 8e- + 8H+ + 16ATP → H2 + 2HN3 + 16(ADP + Pi)

(Ar) 2e- + 2H+ + 4ATP → H2 + 4(ADP + Pi)

Nitrogen fixation and Hydrogen production by nitrogenase