초록
<P><B>Abstract</B></P> <P>pH, known as the most important parameter in H<SUB>2</SUB> fermentation, cannot be precisely controlled in a scaled-up fermenter as in a lab fermenter. In the preset work, to assess the effect of pH control accuracy on H<SUB>2</SUB> fermentation, the pH was controlled at 6.0±0.1, 6.0±0.3, 6.0±0.5, 6.0±0.7, and 6.0±0.9 during batch fermentation of food waste. Up to deviation of ±0.3, a high H<SUB>2</SUB> yield of 1.67–1.73molH<SUB>2</SUB>/mol hexose<SUB>added</SUB> was attained with producing butyrate as a major metabolite (>70% of total organic acids produced). A huge drop of H<SUB>2</SUB> production, however, was observed at deviation >±0.5 with lowered substrate utilization and increased production of lactate. Next generation sequencing results showed that <I>Clostridium</I> was found to be the dominant genus (76.4% of total number of sequences) at deviation of ±0.1, whereas the dominant genus was changed to lactic acid bacteria such as <I>Streptococcus</I> and <I>Lactobacillus</I> with increase of deviation value.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A significant effect of pH control accuracy on H<SUB>2</SUB> fermentation performance. </LI> <LI> High H<SUB>2</SUB> yield and substrate utilization at deviation of ±0.1 and ±0.3. </LI> <LI> Low H<SUB>2</SUB> production with lowered substrate utilization at deviation >±0.5. </LI> <LI> Lactic acid bacteria became dominant with increase of deviation value. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>