The Relationship between the Nitrogen and Carbon Metabolism of Clostridium acetobutylicum

Abstract

Cl. acetobutylicum is able to use protein (wheat gluten and casein), peptone, and amino-acid mixtures (aminoids) as sources of N, with only slight changes in the ratio of solvents produced. There is evidence that it uses part of the amino-acids as such, without deaminization. In presence of aminoids, a large increase in synthesized protein takes place. While the organism cannot use ammonia N alone, it appears to utilize NH4 salts preferentially in presence of protein nitrogen; the maximum utilization with complete fermentation was obtained with ammonium carbonate. NH4 salts of mineral acids were utilized to a far less extent. Ammonia N is used less readily in presence of simple forms of organic N, such as peptone and amino-acids, than in presence of native proteins such as are found in corn. The ratio of solvents is changed if ammonium N is supplied, its effect being due to the acid liberated, which lowers the pH; there also appears to be a specific action of the acid. Nitrate N, as the K or NH4 salt, is not used by the organism alone or in presence of undegraded protein N.