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Table 2 The fermentation performance of EC∆budC∆ldhA strain under different NaHCO3 concentration

From: Co-production of acetoin and succinic acid by metabolically engineered Enterobacter cloacae

NaHCO3 conc. (g L−1) 0 2.5 5 7.5 10
Final pH 5.43 ± 0.58 5.92 ± 0.021 5.94 ± 0.191 6.2 ± 0.127 6.56 ± 0.021
Consumed glucose (g L−1) 67.45 ± 1.626 66.7 ± 4.808 61 ± 3.111 64.65 ± 4.879 67 ± 0.4.667
Final OD600 4.21 ± 0.078 5.155 ± 0.007 5.305 ± 0.064 5.84 ± 0.113 5.79 ± 0.226
Final succinic acid (g L−1) 1.15 ± 0.212 1.5 ± 0.283 1.4 ± 0.141 1.45 ± 0.212 1.55 ± 0.212
Final acetoin (g L−1) 16.45 ± 0.212 15.3 ± 1.273 13.3 ± 0.707 14.7 ± 1.414 12.4 ± 1.556
Final 2,3-BDO (g L−1) 3 ± 0.283 2.65 ± 0.212 2 ± 0.141 2.7 ± 0.283 1.95 ± 0.495
Final lactic acid (g L−1) ND ND ND ND ND
Final acetic acid (g L−1) ND ND 0.9 ± 0 1.2 ± 0 1.5 ± 0.141
Final ethanol (g L−1) 6.25 ± 0.354 6.8 ± 0.283 6.15 ± 0.212 6.05 ± 0.212 6.1 ± 0.566
Succinic acid yield (mol mol−1) 0.026 ± 0.004 0.034 ± 0.004 0.032 ± 0.02 0.034 ± 0.02 0.036 ± 0.01
Acetoin yield (mol mol−1) 0.499 ± 0.018 0.469 ± 0.005 0.446 ± 0.001 0.465 ± 0.01 0.381 ± 0.028
2,3-BDO yield (mol mol−1) 0.089 ± 0.011 0.079 ± 0.001 0.066 ± 0.001 0.083 ± 0.002 0.059 ± 0.019
  1. Each date indicates the mean ± SD from two experiments
  2. ND not detected