초록
<P><B>Abstract</B></P> <P>The biohydrogen production by dark fermentation (DF) of <I>Arundo donax</I> enzymatic hydrolysate, obtained from untreated (ADH) and steam-exploded (ADHexp) biomass, was investigated. A glucose synthetic medium (SM) was also studied for comparison. The main novelty of the manuscript is the use of a new methodology for the selection of H<SUB>2</SUB> producing bacteria at detriment of the methanogenic ones that does not require harsh physico-chemical treatments of the source anaerobic consortium. DF tests were carried out under mesophilic conditions (38 °C) in batch reactors. A mixed culture from an anaerobic digestion plant was used as inoculum for all substrates. The inoculum was pre-cultured in nutrient medium and the progressive adaptation of bacterial consortium to hydrogen production was followed in three sequenced batch tests. In all tests H<SUB>2</SUB> production is maximal in the first 24 h (in parallel to microbial growth). Cumulative H<SUB>2</SUB> volumes approximately double with the progressive adaptation of the microbial consortium. H<SUB>2</SUB> yields obtained after the third batch set on SM, ADH, and ADHexp were 2.00, 3.06, 2.59 ( <SUB> mol <SUB> H 2 </SUB> </SUB> / <SUB> mol glucose </SUB> ) respectively. H<SUB>2</SUB> yields obtained were comparable or higher than literature data confirming the effectiveness of the experimental procedure employed in selecting H<SUB>2</SUB> producers.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Suitability of <I>Arundo donax</I> as substrate for dark fermentation after mild enzymatic hydrolysis. </LI> <LI> Selection of anaerobic consortium for H<SUB>2</SUB> production without any chemical or thermal pre-treatment. </LI> <LI> High bio-hydrogen yields up to 3.0 mol H<SUB>2</SUB> per mol of glucose equivalents. </LI> </UL> </P>