Biohydrogen production by dark fermentation of glycerol using Enterobacter and Citrobacter Sp

• Published in: Biotechnology progress Vol. 29; no. 1; pp. 31 - 38
• Main Authors: Maru, Biniam T., Constanti, Magda, Stchigel, Alberto M., Medina, Francesc, Sueiras, Jesus E.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.01.2013
• Subjects: biohydrogen production; Citrobacter - chemistry; Citrobacter - metabolism; Citrobacter freundii; Enterobacter; Enterobacter - chemistry; Enterobacter - metabolism; Fermentation; glycerol; Glycerol - metabolism; Hydrogen - chemistry; Hydrogen - metabolism; Time Factors
• ISSN: 8756-7938; 1520-6033
• DOI: 10.1002/btpr.1644

Glycerol is an attractive substrate for biohydrogen production because, in theory, it can produce 3 mol of hydrogen per mol of glycerol. Moreover, glycerol is produced in substantial amounts as a byproduct of producing biodiesel, the demand for which has increased in recent years. Therefore, hydrogen production from glycerol was studied by dark fermentation using three strains of bacteria: namely, Enterobacter spH1, Enterobacter spH2, and Citrobacter freundii H3 and a mixture thereof (1:1:1). It was found that, when an initial concentration of 20 g/L of glycerol was used, all three strains and their mixture produced substantial amounts of hydrogen ranging from 2400 to 3500 mL/L, being highest for C. freundii H3 (3547 mL/L) and Enterobacter spH1 (3506 mL/L). The main nongaseous fermentation products were ethanol and acetate, albeit in different ratios. For Enterobacter spH1, Enterobacter spH2, C. freundii H3, and the mixture (1:1:1), the ethanol yields (in mol EtOH/mol glycerol consumed) were 0.96, 0.67, 0.31, and 0.66, respectively. Compared to the individual strains, the mixture (1:1:1) did not show a significantly higher hydrogen level, indicating that there was no synergistic effect. Enterobacter spH1 was selected for further investigation because of its higher yield of hydrogen and ethanol. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2013