Abstract
Various anaerobes were cultivated in media containing glucose. When 100 ml of thioglycollate medium containing 2.0% (w/v) glucose was used, Clostridium butyricum ATCC 859, NBRC 3315, and NBRC 13949 evolved 227-243 ml of biogas containing about 180 ml of hydrogen in one day. C. butyricum NBRC 3315 and Enterobacter aerogenes NBRC 13534 produced hydrogen in the presence of glucose or pyruvic acid. When a medium containing 0.5% (w/v) yeast extract and 2.0% (w/v) glucose, E. aerogenes NBRC 13534 evolved more biogas and hydrogen than C. butyricum NBRC 3315 in the absence of reducing agent. When E. aerogenes NBRC 13534 was cultivated under pH control at 5.0, the doubling time of the cell was longest, maximum optical density of the culture was lowest, and the rate of glucose consumption was slowest in all cultivation under pH control at 5-7. However, the rate of hydrogen accumulation was fastest and final volume of accumulated hydrogen was highest.
