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The fermentation stoichiometry of Thermotoga neapolitana and influence of temperature, oxygen, and pH on hydrogen production
Author(s) -
Munro Sarah A.,
Zinder Stephen H.,
Walker Larry P.
Publication year - 2009
Publication title -
biotechnology progress
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 129
eISSN - 1520-6033
pISSN - 8756-7938
DOI - 10.1002/btpr.201
Subject(s) - fermentation , yield (engineering) , oxygen , stoichiometry , food science , hydrogen production , chemistry , hydrogen , biochemistry , catalysis , organic chemistry , materials science , metallurgy
Abstract The hyperthermophilic bacterium, Thermotoga neapolitana , has potential for use in biological hydrogen (H 2 ) production. The objectives of this study were to (1) determine the fermentation stoichiometry of Thermotoga neapolitana and examine H 2 production at various growth temperatures, (2) investigate the effect of oxygen (O 2 ) on H 2 production, and (3) determine the cause of glucose consumption inhibition. Batch fermentation experiments were conducted at temperatures of 60, 65, 70, 77, and 85°C to determine product yield coefficients and volumetric productivity rates. Yield coefficients did not show significant changes with respect to growth temperature and the rate of H 2 production reached maximum levels in both the 77°C and 85°C experiments. The fermentation stoichiometry for T. neapolitana at 85°C was 3.8 mol H 2 , 2 mol CO 2 , 1.8 mol acetate, and 0.1 mol lactate produced per mol of glucose consumed. Under microaerobic conditions H 2 production did not increase when compared to anaerobic conditions, which supports other evidence in the literature that T. neapolitana does not produce H 2 through microaerobic metabolism. Glucose consumption was inhibited by a decrease in pH. When pH was adjusted with buffer addition cultures completely consumed available glucose. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009