Abstract
Many of N2-fixing cyanobacterial strains have two types of [NiFe]-hydrogenase: an uptake hydrogenase (Hup) and a bidirectional hydrogenase (Hox). The biosynthetic pathways leading to active [NiFe]-hydrogenase formation are complex processes that require the collaboration of Hyp (Hydrogenase pleiotropy). HypF is involved in the CO and CN ligand syntheses of [NiFe]-cluster from carbamoyl phosphate and also has a central role in assembly of the cluster. To see if disruption of hypF gene is beneficial to photobiological H2 production by N2-fixing cyanobacteria, we have constructed two hypF disruption mutants from Anabaena sp. PCC 7120 wild-type and the ΔhupL mutant: ΔhypF and ΔhypF/ΔhupL. These mutants showed high H2 production activity at a rate 5 to 8 times that of wild-type under nitrogen-fixing conditions. The disruption of hypF seems to be useful as an alternative means for improvement of hydrogen production in nitrogenase based system.
