BioChem - DOS

Effect of organic loading rate and solids retention time on microbial population during bio-hydrogen production by dark fermentation in large lab-scale

International journal of hydrogen energy

Mariakakis, I.; Bischoff, P.; Krampe, J.; Meyer, C.; Steinmetz, H.

<P><B>Abstract</B></P><P>The experimental investigation aimed at the study of the microbial population during the continuous operation of a complete mixed reactor in large lab-scale (30&nbsp;L) by variation of the Organic Loading Rate (OLR) and Sludge Retention Time (SRT) ranging from 10&nbsp;g sucrose/(L&#x2219;d) to 30&nbsp;g/(L&#x2219;d) and from 12&nbsp;h to 48&nbsp;h respectively. H<SUB>2</SUB> yield reached to 1.72&nbsp;mol H<SUB>2</SUB>/mol hexose for HRT&nbsp;&equals;&nbsp;1.6&nbsp;d and OLR&nbsp;&equals;&nbsp;20&nbsp;g sucrose/(L&#x2219;d). In each phase the dominant microbial genera were identified by sequencing after a Polymerase Chain Reaction (PCR) with universal primers for the domains of <I>Archaea</I> and <I>Eubacteria</I> and specific for <I>Clostridium</I> species and genetic material isolation by Denaturing Gradient Gel Electrophoresis (PCR-DGGE). The phylogenetic analyses showed that hydrogen producing <I>Clostridium</I> species could be affiliated in all experimental phases. Other dominant genera were affiliated mainly to <I>Ethanoligenes harbinense</I> and uncultured <I>Prevotella</I> and <I>Selonomonas</I> species. Bio-hydrogen production was associated to a mixed butyric/ethanol type fermentation facilitated mainly by <I>Clostridium tyrobutyricum</I> and <I>E</I>. <I>harbinense</I> in the presence of lactate as intermediate metabolic product.</P> <P><B>Highlights</B></P><P>&#x025BA; A large lab-scale reactor was successfully operated for 120&nbsp;d. &#x025BA; H<SUB>2</SUB> yield reached 1.72&nbsp;mol H<SUB>2</SUB>/mol hexose for HRT&nbsp;&equals;&nbsp;1.6&nbsp;d and OLR&nbsp;&equals;&nbsp;20&nbsp;g sucrose/(L&#x2219;d). &#x025BA; No hydrogen production could be established for OLR lower than 10&nbsp;g sucrose/(L&#x2219;d). &#x025BA; No significant shift or changes in the bacterial population have been observed. &#x025BA; A mixed butyric/ethanol fermentation was the main pathway for hydrogen production.</P>

2011

Elsevier

0360-3199

1879-3487

36

17

pp.10690-10700

10.1016/j.ijhydene.2011.06.008

http://click.ndsl.kr/servlet/OpenAPIDetailView?keyValue=05787966&target=NART&cn=NART57146253

Bio-hydrogen; Dark fermentation; Organic loading rate; solids retention time; PCR-DGGE; Clostridium