|High photobiological hydrogen production activity of a Nostoc sp. PCC 7422 uptake hydrogenase-deficient mutant with high nitrogenase activity|Yoshino, F.; Ikeda, H.; Masukawa, H.; Sakurai, H. (2007). High photobiological hydrogen production activity of a Nostoc sp. PCC 7422 uptake hydrogenase-deficient mutant with high nitrogenase activity. Mar. Biotechnol. 9(1): 101-112. dx.doi.org/10.1007/s10126-006-6035-3
In: Marine Biotechnology. Springer-Verlag: New York. ISSN 1436-2228, more
Hydrogen; Nitrogenase; Marine
|Authors|| || Top |
- Yoshino, F.
- Ikeda, H.
- Masukawa, H.
- Sakurai, H.
We describe a strategy to establish cyanobacterial strains with high levels of H2 production that involves the identification of promising wild-type strains followed by optimization of the selected strains using genetic engineering. Nostoc sp. PCC 7422 was chosen from 12 other heterocystous strains, because it has the highest nitrogenase activity. We sequenced the uptake hydrogenase (Hup) gene cluster as well as the bidirectional hydrogenase gene cluster from the strain, and constructed a mutant (ΔhupL) by insertional disruption of the hupL gene. The ΔhupL mutant produced H2 at 100 μmoles mg chlorophyll a-1 h-1, a rate three times that of the wild-type. The ΔhupL cells could accumulate H2 to about 29% (v/v) accompanied by O2 evolution in 6 days, under a starting gas phase of Ar + 5% CO2. The presence of 20% O2 in the initial gas phase inhibited H2 accumulation of the ΔhupL cells by less than 20% until day 7.