Table 9.3 shows the hydrogen yields and chief metabolites for major hydrogen
fermentation bacteria. Because many bacteria metabolically produce butyric acid,
acetic acid, and lactic acid, and because these organic acids are present in fermentation waste, the processing or use of this waste poses major issues for
hydrogen fermentation.
9.4.2 Bacterial Hydrogen Production Rate and Yields
Many hydrogen-producing bacteria have been reported to date. Table 9.4 shows
leading bacteria that have been found to produce hydrogen at a fast rate or with high
substrate yields. Because yields and rates differ for batch culturing and continuous
culturing, the two are shown separately. Continuous culturing of the same bacteria
results in higher bacterial density in the fermentation tank, which can increase the
hydrogen production rate.
Fig. 9.6 Major metabolic pathway for bacteria under anaerobic conditions
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fermentation bacteria. Because many bacteria metabolically produce butyric acid,
acetic acid, and lactic acid, and because these organic acids are present in fermentation waste, the processing or use of this waste poses major issues for
hydrogen fermentation.
9.4.2 Bacterial Hydrogen Production Rate and Yields
Many hydrogen-producing bacteria have been reported to date. Table 9.4 shows
leading bacteria that have been found to produce hydrogen at a fast rate or with high
substrate yields. Because yields and rates differ for batch culturing and continuous
culturing, the two are shown separately. Continuous culturing of the same bacteria
results in higher bacterial density in the fermentation tank, which can increase the
hydrogen production rate.
Fig. 9.6 Major metabolic pathway for bacteria under anaerobic conditions
9.4 Biohydrogen Production
317