Improvement of photobiological hydrogen production in Chlorococcum minutum using various oxygen scavengers

The depletion of non-renewable energy resources such as fossil fuels urge the human society to concentrate more on renewable energy including production of biological hydrogen (H₂) from algae. Biological hydrogen or biohydrogen is one of the cleanest and efficient alternate energy sources for human needs. It is a well-known fact that hydrogenase (H₂ase) will work in anoxic condition which is the key enzyme in H₂ generation from photosynthetic algae or advanced plants. Keeping in view the significance of anoxic condition, the present study deals with screening of three oxygen scavengers/removers such as sodium sulfite (Na₂SO₃), sodium metabisulfite (Na₂S₂O₅) and sodium dithionite (Na₂S₂O₄) individually along with universal tris-acetate-phosphate (TAP) medium for improvement of biohydrogen production in green alga Chlorococcum minutum (C. minutum) under in vitro conditions. To the best of our knowledge, for the first time improvement in hydrogen production was achieved using sodium sulfite and sodium metabisulfite individually with algal cultures. Efficient photobiological H₂ production was observed at 24 h in C. minutum in the presence of all the three oxygen scavengers when compared to untreated samples via limiting the oxygen levels but output was more with sodium sulfite treatment. Particularly 0.8 mM Na₂SO₃ is best for enhancement of H₂ production at 24 h when compared to other two scavengers and this may be due to high oxidation state and more electron negativity of this compound. Apart from augmentation in H₂ production in this species, present screening may also be helpful for researchers working in the area of biological H₂ generation.