TABLE 1.

Examples of published rates of cyanobacterial H2 formation

CyanobacteriumEnzymeConditionH2 formation rate (μmol/mg chlorophyll·h)Reference(s)
Synechocystis PCC 6803Bidirectional hydrogenaseLight + glucose6 51
Arthrospira (Spirulina) maximaBidirectional hydrogenaseAutofermentation, dark, 35°C0.75-1.5 3
Anabaena azotica Mo nitrogenaseC2H2 + H29 34
V nitrogenaseC2H2 + H240 34
Anabaena variabilis Mo nitrogenaseC2H2 + H224 34
Nostoc (Anabaena) sp. PCC 7120Mo nitrogenase hupL/hoxL-deficient mutants50 139
Anabaena variabilis Mo nitrogenaseImmobilized cells, continuously for 5 months0.06-0.6 134
Anabaena variabilis Mo nitrogenaseImmobilized cells, sustained production after extensive CO2fixation53 137
Anabaena variabilis Mo nitrogenase hupSL mutant135 92
Anabaena variabilis PK84V nitrogenaseHydrogenase mutant260 27 (Fig. 3)
Anabaena cylindrica Bidirectional hydrogenaseAnaerobic incubation, high light intensity34 119
Anabaena variabilis PK84Mo nitrogenaseHydrogenase-defective isolate19 126
Synechococcus PCC 7942Clostridial hydrogenase IHeterologous expression, activity in cell extracts45 8
Wild typeActivity in cell extracts14
Thermosynechococcus elongatus Uptake hydrogenaseModified PsaE protein of PSI coupled with Ralstonia eutropha hydrogenase0.3 103, 104