Requirement of an alkaline pH and ammonia for substrate oxidation by Bacillus pasteurii.

Wiley, W. R. (Washington State University, Pullman) and J. L. Stokes. Requirement of an alkaline pH and ammonia for substrate oxidation by Bacillus pasteurii. J. Bacteriol. 84:730-734. 1962-Resting-cell suspensions of Bacillus paseurii require a pH higher than 8.0 and also NH(4) (+) for the oxidation of glycine, alanine, serine, glutamic acid, other amino acids, and compounds of the Krebs cycle. The optimal pH is 9.2. Maximal activity was obtained with 0.5% (NH(4))(2)SO(4), the highest concentration tested. NH(4) (+) can be supplied by a number of inorganic and organic ammonium salts. The effect of NH(4) (+) is fairly specific. It cannot be replaced by Na(+), Cs(+), and Mg(++), and only partially replaced by Li(+), K(+), Rb(+), and Ca(++). Some possible metabolic functions of the required alkaline pH and NH(4) (+) are discussed.