Accumulation of freely extractable glutamic acid by lactic acid bacteria.

Gale (2, 3) initially described the existence in bacteria of a metabolism-dependent process achieving the accumulation of freely extractable amino acids. During the studies described here a number of additional reports have appeared citing examples of amino acid (4, 5), carbohydrate (6), and phosphate (7) accumulations in bacteria. The mechanism of these accumulations is unknown. Christensen et al. (8) have observed that pyridoxal stimulates amino acid uptake by Ehrlich ascites tumor cells. This and a companion paper describe an investigation intended to determine whether vitamin Bs deprivation influences the activity of a bacterial amino acid accumulation system. The lactic acid bacteria were selected for study in view of the ease with which the intracellular vitamin B6 content can be varied in this group of organisms (9). A description of glutamic acid accumulation in several species is presented here. The following paper (10) summarizes experiments designed to test the effect of vitamin Bg deficiency on the accumulation process.