초록
<P><B>Abstract</B></P> <P>This study addresses for the first time the influence of initial pH on the evolution of microbial consortia in dark fermentation of scotta permeate, using a high-throughput sequencing approach. Three fermentation phases could be detected: 1) a lag phase with no substantial differences in microbial composition at different initial pH values; 2) an exponential H<SUB>2</SUB> production phase, accompanied by a general increase of <I>Clostridium</I> genus components and higher incidence of <I>Trichococcus</I> genus at neutral and alkaline pH; 3) a final stationary phase, characterized by a general increase of <I>Bifidobacterium</I> and <I>Lactobacillus</I> genera in all reactors. The initial pH value influenced the relative abundance of <I>Trichococcus</I> at 16–48 h of incubation. The metabolic activity of this genus increased the amount of metabolic precursors of H<SUB>2</SUB> so that, when pH lowered to 5.4, clostridia in the reactors with initial alkaline pH become more active H<SUB>2</SUB>-producers than those in the others.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Initial pH influences H<SUB>2</SUB> production from scotta permeate. </LI> <LI> pH does not affect the microbial alfa diversity between reactors. </LI> <LI> However, pH does affect the relative abundance of microbial groups. </LI> <LI> The genus <I>Trichococcus</I> exerts a key role in H<SUB>2</SUB> production at alkaline pH values. </LI> <LI> Microbial consortia composition can be oriented to optimum H<SUB>2</SUB> production by acting on initial pH. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>