초록
<P><B>Abstract</B></P> <P>For deeply understanding the H<SUB>2</SUB> production promotion mechanism by adding Mg<SUP>2+</SUP> and Fe<SUP>2+</SUP> in <I>Ethanoligenens harbinense</I> fermentation process, the effects on cell growth, liquid byproducts production and H<SUB>2</SUB> yield at growth level were investigated, meanwhile the expressions of [FeFe]-hydrogenase, acetate kinase, alcohol dehydrogenase and lactate dehydrogenase with quantitative reverse transcription PCR at transcript level were monitored. The experimental results indicated that Mg<SUP>2+</SUP> makes more contributions on cell growth, but with Mg<SUP>2+</SUP> concentration increasing the expressions of functional genes were obviously suppressed. Fe<SUP>2+</SUP> has slightly positive effects on increasing cell growth and functional genes expression, which is inferred the reason of H<SUB>2</SUB> production enhancement. A maximum hydrogen yield of 2.14 mol-H<SUB>2</SUB>/mol-glucose was obtained in optimal medium supplemented with 600 mg/l MgCl<SUB>2</SUB>·6H<SUB>2</SUB>O and 100 mg/l FeSO<SUB>4</SUB>·7H<SUB>2</SUB>O. The realization of hydrogen production enhancement of <I>E. harbinense</I> by adding promoting factors was not only realized through increasing cell biomass growth and hydrogenase activity, but also some promotion effects on functional enzyme genes expressions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Mechanisms of bio-H<SUB>2</SUB> production enhancement by metal ions were investigated. </LI> <LI> Monitor experiments at cell growth level and gene transcript level. </LI> <LI> Transcript variety analysis of <I>hyd</I>A, acetate kinase, alcohol dehydrogenase and lactate dehydrogenase. </LI> </UL> </P>