Use of Glutamic Acid to Supplement Fluid Medium for Cultivation of Bordetella pertussis

ABSTRACT

The amino acid consumption by Bordetella pertussis growing in broth containing casein hydrolysate was examined. Serine, proline, alanine, glycine, aspartate, and glutamate were rapidly consumed, in a manner which suggested that they supplied the energy requirements of the organism; exhaustion of the energy source appeared to be the main factor limiting the yield of cells. There was no correlation between the utilization of individual amino acids and the phase of growth; uptake appeared to depend only upon relative concentrations. Consumption of threonine, phenylalanine, histidine, leucine, and methionine was slight; consumption of valine and lysine was variable, and isoleucine was excreted. The addition of monosodium l-glutamate (3 mg/ml) to the broth in shaken flasks increased the cell yield by an average of 43.5%. It had no detectable adverse effect upon the agglutin-producing capacity, agglutinability in antisera versus smooth and rough growth phases, mouse-lethal toxicity, histamine-sensitizing factor potency, or intracerebral protective potency of the culture. Broth supplemented with monosodium l-glutamate has been used over a 2-year period to prepare experimental vaccines by both batch and continuous cultivation methods at controlled pH; the cell yields obtained from the supplemented broth have been up to 52% higher than those from the basal broth. The use of glutamate to replace a proportion of casein hydrolysate in the broth caused a reduction in the cell yield, an alteration in cell morphology, and reduction in the mouse-lethal toxicity, the histamine-sensitizing factor potency, and the intracerebral protective potency of the cells.