Open AccessHydrogen metabolism of three unicellular nitrogen‐fixing cyanobacteria
Author(s) -
Oost John,
Kannwworff Wouter A.,
Krab Klaas,
Kraayenhof Ruud
Publication year - 1987
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1987.tb02512.x
Subject(s) - hydrogenase , cyanobacteria , nitrogen fixation , nitrogenase , trichodesmium , hydrogen production , biochemistry , hydrogen , chemistry , oxygen , nitrogen , carbon fixation , photosynthesis , biology , diazotroph , enzyme , bacteria , catalysis , organic chemistry , genetics
The enzyme activities responsible for the evolution and consumption of hydrogen in three unicellular cyanobacteria were investigated. Gloeothece sp. 6909 and Cyanothece sp. 7822 performed an oxygen‐tolerant nitrogen fixation, whereas the nitrogenase activity of Synechococcus sp. 7425 was much more sensitive to oxygen. While in Gloeothece the net hydrogen production during nitrogen fixation was relatively low due to recycling by an uptake hydrogenase, little hydrogen consumption was detected in Cyanothece and Synechococcu . On the other hand a reversible hydrogenase was demonstrated in the latter strains. However, only Cyanothece shows hydrogenase‐catalysed hydrogen production in vivo under anaerobic conditions in the dark. It is suggested that hydrogen is a fermentation product, and that the physiological function of this reversible hydrogenase is the removal of excess reduction equivalents under such conditions.