Predicting proteome allocation, overflow metabolism, and metal requirements in a model acetogen
Fig 3
Predictions of growth rate and product production.
(A) Two sets of predicted growth rates, from iJL680 and iJL965-ME, were plotted against in vivo measured growth rates for arginine, xylose, pyruvate, glucose, CO, and fructose growth conditions (±std, n = 3). Linear regressions and 95% confidence intervals were represented by dashed lines and shaded areas, respectively. In iJL680, carbon atom uptake was constrained to 30 mmol*gDW-1*h-1, while in iJL965-ME, the optimal carbon uptake was constrained by inherent proteome limitations. r and p represent Pearson's correlation and p-value. (B) Predicted maximum acetate secretion rate (Ac; mmol*gDW-1*h-1) to substrate uptake rate (SUR; mmol*gDW-1*h-1) was plotted against measured averaged values. (C) Predicted pathway mechanism for observed glycerol production in spent media. Glycerol was a byproduct of cell membrane formation during cardiolipin production. While the cell was carbon-limited, glycerol was recycled into biomass using the pathway highlighted in green. When cells were proteome-limited, C. ljungdahlii secreted glycerol (purple arrow). Abbreviations: 1 = phosphatidylglycerol (n-C14:0), 2 = cardiolipin (n-C14:0), 3 = glycerol, 4 = dihydroxyacetone, 5 = dihydroxyacetone phosphate, CLPNS140 = cardiolipin synthase (n-C14:0), GLYCt = glycerol transport, GLYCDx = glycerol dehydrogenase, DHAK = dihydroxyacetone kinase.