An integrated dark fermentation and microbial electrochemical cell (MEC) process was evaluated for
hydrogen production from sugar beet juice. Different substrate to inoculum (S/X) ratios were tested
for dark fermentation, and the maximum hydrogen yield was 13% of initial COD at the S/X ratio of 2
and 4 for dark fermentation. Hydrogen yield was 12% of initial COD in the MEC using fermentation liquid
end products as substrate, and butyrate only accumulated in the MEC. The overall hydrogen production
from the integrated biohydrogen process was 25% of initial COD (equivalent to 6 mol H2/mol hexoseadded),
and the energy recovery from sugar beet juice was 57% using the combined biohydrogen