Effects of Ethanolamine as a nitrogen source on hydrogen production by Rhodobacter capsulatus.
Ethanolamine was examined as a nitrogen source in the production of hydrogen by Rhodobacter capsulatus ST-410, a hydrogenase-deficient mutant of the strain B-100. It was found that ethanolamine supports cell growth as the sole nitrogen source and permits a large amount of hydrogen evolution, detected at 138 micromol/ml-culture from 3.5 mM ethanolamine and 30 mM DL-malate. The amount corresponded to a stoichiometric yield of 77% and was close to that obtained from 7.0 mM L-glutamate and 30 mM DL-malate. The hydrogen evolution rate per unit biomass (cells) was higher than that with L-glutamate, and the cells grown with ethanolamine had higher nitrogenase activity than the cells grown with L-glutamate. In terms of bioconversion of cellulosic and hemicellulosic biomass to hydrogen, D-glucose, D-xylose, and D-cellobiose were tested as substrates. The results indicated that those sugars permit a large evolution of hydrogen through cultivation with ethanolamine as a nitrogen source. For instance, the cells grown with 3.5 mM ethanolamine evolved hydrogen of 289 micromol/ml-culture (80% yield) from 30 mM D-glucose under a controlled pH of 6.4 to 6.9.
Katsuda
T
T
Department of Bioapplied Chemistry, Osaka City University, Osaka, Japan.
Azuma
M
M
Kato
J
J
Takakuwa
S
S
Ooshima
H
H
D019856:Ethanolamine / Q000378:metabolism*; D006859:Hydrogen / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism*; D009591:Nitrogenase / Q000378:metabolism; D016354:Rhodobacter capsulatus / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*
D019856:Ethanolamine; D006859:Hydrogen; D009591:Nitrogenase; D009584:Nitrogen