%0 Journal Article %A White, P. J %T Inhibition by d-Glutamate as the Cause of Diphasic Growth of Bacillus megaterium NCIB 7581 with Glycerol plus dl-Glutamic Acid %D 1979 %J Microbiology, %V 114 %N 1 %P 149-158 %@ 1465-2080 %R https://doi.org/10.1099/00221287-114-1-149 %I Microbiology Society, %X SUMMARY: Growth of Bacillus megaterium NC1B 7581 in a simple chemically defined medium was inhibited by d-glutamate above 0·01 mg ml−1; equimolar l-glutamate prevented this inhibition. When dl-glutamate (2 mg ml−1) was present in the medium (with glycerol as the main carbon source), organisms grew exponentially until all the l-isomer had disappeared; growth then stopped for about 24 h during which there was a transient appearance of d-glutamine in the medium. Throughout the first stationary phase the concentration of d-glutamate in the medium fell continuously and when it was less than 0·01 mg ml−1 there was a second phase of growth. Exponential phase organisms growing without glutamate contained only 4 mm-glutamate in the free amino acid pool. During the first stationary phase with d l-glutamate added to the medium, the concentration of glutamate (all d-isomer) was 47 mm in the pool. Of four other strains of B. megaterium tested, only one was sensitive to d-glutamate. From strain 7581 a d-glutamate-resistant substrain was easily developed. Among other amino acids added singly to the defined medium, only d- (and l-) serine was inhibitory to all five strains examined. Inhibition of B. megaterium 7581 by d-glutamate was prevented by single addition of several amino acids, each of which could act as a sole source of nitrogen for growth. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-114-1-149