초록
<P>Formate is recognized as a superior substrate for biological H<SUB>2</SUB> production by several bacteria. However, the growth of a single organism coupled to this energetic pathway has not been shown in mesophilic conditions. In the present study, a bioreactor with gas sparging was used, where we observed for the first time that H<SUB>2</SUB> production from formate can be coupled with growth of the model sulfate-reducing bacterium <I>Desulfovibrio vulgaris</I> in the absence of sulfate or a syntrophic partner. In these conditions, <I>D. vulgaris</I> had a maximum growth rate of 0.078 h<SUP>–1</SUP> and a doubling time of 9 h, and the Δ<I>G</I> of the reaction ranged between −21 and −18 kJ mol<SUP>–1</SUP>. This is the first report of a single mesophilic organism that can grow while catalyzing the oxidation of formate to H<SUB>2</SUB> and bicarbonate. Furthermore, high volumetric and specific H<SUB>2</SUB> production rates (125 mL L<SUP>–1</SUP> h<SUP>–1</SUP> and 2500 mL g<SUB>dcw</SUB><SUP>–1</SUP> h<SUP>–1</SUP>) were achieved in a new bioreactor designed and optimized for H<SUB>2</SUB> production. This high H<SUB>2</SUB> production demonstrates that the nonconventional H<SUB>2</SUB>-producing organism <I>D. vulgaris</I> is a good biocatalyst for converting formate to H<SUB>2</SUB>.</P><P><B>Graphic Abstract</B><BR><IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/esthag/2015/esthag.2015.49.issue-24/acs.est.5b02251/production/images/medium/es-2015-02251a_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/es5b02251'>ACS Electronic Supporting Info</A></P>