초록
<P><B>Abstract</B></P> <P>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 (H<SUB>2</SUB>) 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 (H<SUB>2</SUB>ase) will work in anoxic condition which is the key enzyme in H<SUB>2</SUB> 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 (Na<SUB>2</SUB>SO<SUB>3</SUB>), sodium metabisulfite (Na<SUB>2</SUB>S<SUB>2</SUB>O<SUB>5</SUB>) and sodium dithionite (Na<SUB>2</SUB>S<SUB>2</SUB>O<SUB>4</SUB>) individually along with universal tris-acetate-phosphate (TAP) medium for improvement of biohydrogen production in green alga <I>Chlorococcum minutum</I> (<I>C. minutum</I>) under <I>in vitro</I> 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 H<SUB>2</SUB> production was observed at 24 h in <I>C. minutum</I> 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 Na<SUB>2</SUB>SO<SUB>3</SUB> is best for enhancement of H<SUB>2</SUB> 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 H<SUB>2</SUB> production in this species, present screening may also be helpful for researchers working in the area of biological H<SUB>2</SUB> generation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Oxygen scavengers used in <I>Chlorococcum minutum</I> cultures to improve H<SUB>2</SUB> generation. </LI> <LI> Initially Na<SUB>2</SUB>SO<SUB>3</SUB>, Na<SUB>2</SUB>S<SUB>2</SUB>O<SUB>5</SUB> and Na<SUB>2</SUB>S<SUB>2</SUB>O<SUB>4</SUB> individually used to eliminate oxygen. </LI> <LI> First time H<SUB>2</SUB> production achieved with Na<SUB>2</SUB>SO<SUB>3</SUB> or Na<SUB>2</SUB>S<SUB>2</SUB>O<SUB>5</SUB> in algae. </LI> <LI> All the three scavengers enhanced the H<SUB>2</SUB> production in <I>C. minutum</I> at 24 h. </LI> <LI> Among all, Na<SUB>2</SUB>SO<SUB>3</SUB> (0.8 mM) proved best with respect to H<SUB>2</SUB> generation in <I>C. minutum</I>. </LI> </UL> </P>