Nitrogen Assimilation by Bacillus licheniformis Organisms Growing in Chemostat Cultures

Abstract

SUMMARY: Medium composition influenced the synthesis and breakdown of glutamic acid and alanine by Bacillus licheniformis examined in a chemostat. With ammonia in growth-limiting quantities as the sole nitrogen source, glutamate was synthesized from 2-oxoglutarate via glutamine synthetase and glutamine amide 2-oxoglutarate amino transferase (NADP; oxidoreductase), and alanine was formed from glutamate and pyruvate by transamination. With excess nitrogen, as either alanine or glutamate, a carbon-limited culture synthesized respectively NAD-linked alanine dehydrogenase or NADP-linked glutamate dehydrogenase, and the latter two enzymes performed only a catabolic role. If, however, nitrogen was supplied as alanine or glutamate to a nitrogen-limited culture, then synthesis of alanine dehydrogenase and glutamate dehydrogenase was repressed. Correlations were drawn between the nature of the growth environment, the composition of the amino acid pools and the synthesis of the above mentioned enzymes in B. licheniformis.