Sodium (Na+) concentration effects on metabolic pathway and estimation of ATP use in dark fermentation hydrogen production through stoichiometric analysis.
Batch experiments were conducted to investigate the effects of Na(+) concentration on hydrogen production with dark fermentation. The Na(+) concentration was varied from 0 to 8 g/L in the mixed culture using an anaerobic sludge treated by acid. The maximum hydrogen production was achieved with 1 g-Na(+)/L, whereas the hydrogen production was decreased over 2 g-Na(+)/L due to the inhibitory of Na(+). The mechanisms of Na(+) inhibition to the hydrogen production are studied using pure culture of Clostridium butyricum by calculating the energy balance. At a high sodium concentration, C. butyricum used a greater proportion of the ATP generated via fermentation for cell maintenance rather than for cell synthesis. Additionally, higher Na(+) concentrations shifted the fermentation process toward the acetate synthesis pathway instead of the butyrate pathway, and the value of Y(X/ATP) decreased. With high Na(+) concentrations, a greater ratio of hydrogen was produced via the oxidation of NADH. Excess hydrogen production decreased as the Na(+) concentration increased.
Department of Environmental Science and Engineering, Center for Environmental Studies, Kyung Hee University, Seochon-dong, Giheung-gu, Yongin-si, Gyeonggi-do 446-701, Republic of Korea.
Myoung-Joo
MJ
Lee
Tae-Hyeong
TH
Kim
Booki
B
Min
Sun-Jin
SJ
Hwang
D000255:Adenosine Triphosphate / Q000378:metabolism; D056804:Biofuels; D002087:Butyrates / Q000378:metabolism; D046972:Clostridium butyricum / Q000378:metabolism*; D005285:Fermentation; D006859:Hydrogen / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*
D056804:Biofuels; D002087:Butyrates; D006859:Hydrogen; D000255:Adenosine Triphosphate; D012964:Sodium