Anne-Marie Cromwick

Bacillus licheniformis ATCC 9945A produces γ-poly(glutamic acid) (γ-PGA) when using glutamate, citrate, and glycerol in combination as media carbon sources. Also, various aspects of B. licheniformis cellular physiology are affected by the concentration of Mn(II) salts in culture media. Thus, the metabolism of carbon sources into γ-PGA as a function of MnSO4 concentration was studied by enriching the media with either L-[1,2-13C]glutamic acid (NH2—2CH(1COOH)—(CH2)2-COOH) or [1,5-13C]citric acid (HOO1C—CH2—C(OH)(COOH)—CH2—5COOH) at two media MnSO4 concentrations (615 and 0 μM). Enrichment factors (EF) from 13C-NMR spectra were calculated from the ratio of peak intensities from 13C-enriched γ-PGA divided by the ratio of peak intensities for nonenriched γ-PGA. EF values were than used to determine the percentage of repeat units that were formed from glutamate and citrate. The percentage of repeat units formed from provided glutamate at the 0 and 615 μM Mn(II) media concentrations was 89...

Bacillus licheniformis ATCC 9945A was grown on Medium E in batch fermentations in which the pH was maintained at 5.5., 6.5, 7.4, and 8.25. The effects of pH on cell growth, carbon source utilization, and γ-polyglutamic acid (γ-PGA) production, molecular weight, and polymer ...