The filamentous non-heterocystous cyanobacterium Oscillatoria chalybea showed molecular
hydrogen photoevolution under different conditions. The major part of determined
hydrogen evolution would be derived from a hydrogenase system distinct from the
nitrogenase. To improve the hydrogen production, different buffers, temperatures, pH
values and some inorganic cofactors were studied. The results revealed that the best buffer
was Tricine-KCl, the optimum temperature was 25
C, the optimum pH value was within
the range 7e7.5 and the optimum concentration of nickel chloride was 50 mM that
improved also the growth of O. chalybea. The influence of inorganic cofactors showed that
the addition of 105 MnCl2 increases the photoevolution of molecular hydrogen