抄録
Investigations were carried out on the effect of the amount of available oxygen upon the metabolisms of carbonaceous substances in coli-aerogenes bacteria. When E. coli was grown in the presence of glucose, a gentle aeration (a small supply of air) suppressed the accumulation of lactate against increasing the productions of acetate, carbon dioxide and of the bacterial cell. α-Ketoglutarate-fermentation occurred only under a large supply of air. When the cells of coli-aerogenes were incubated under the low levels of oxygen, not only glucose, C3- (pyruvic, lactic), C4-dicarboxylic and C6-tricarboxylic acids but also acetic acid were mainly oxidized to carbon dioxide and water, but little or no formation of a-ketoglutaric acid occurred. The production of α-ketoglutaric acid from various organic acids except C6-tricarboxylic acids also took place only under the high levels of available oxygen. It was concluded that the direction of oxidative metabolism of substrate-carbon was changeable according to variation of the environmental oxygen level. Relationships among respiration, oxidative fermentation and oxidative assimilation were investigated under various levels of available oxygen.
