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. 2007 Jan 26;189(7):2813–2824. doi: 10.1128/JB.01701-06

TABLE 2.

Results for pH-regulated batch cultures of the fnr mutant and its parent strain, B. cereus F4430/73a

Parameter or yield Value under indicated growth conditions
Aerobic (respiration)
Anaerobic
Fermentation
Fumarateb respiration
Nitrateb respiration
WT fnr WT fnr WT fnr WT fnr
Initial ORP (mV) +280 +280 +47 NG +77 NG +180 +180
Final ORP (mV) +160 +160 −57 NG −14 NG +5 +73
Growth parameters
    μmax (h−1) 1.4 1.1 0.9 NG 0.9 NG 1.0 1.0
    Final biomass (g/liter) 2.5 2.8 0.8 NG 0.8 NG 1.0 0.5
    Glucose consumed (%) 100 100 100 NG 100 NG 100 12
    Nitrate consumed (%) ND ND ND NG ND NG 100 99
    Residual nitrite (mM) ND ND ND NG ND ND 0.1 0.7
Yields of end products (mol/mol of glucose)
    Biomassc 0.83 0.93 0.27 NG 0.25 NG 0.34 1.40
    Lactate NZ NZ 1.40 NG 1.24 NG 0.90 0.5
    Acetate 0.96 0.56 0.29 NG 0.22 NG 0.73 1.11
    Formate NZ NZ 0.34 NG 0.52 NG 0.56 0.43
    Ethanol NZ NZ 0.08 NG 0.18 NG NZ NZ
    Succinate NZ 0.94 0.04 NG 0.05 NG 0.10 0.21
Carbon recovered (%)d 39 73 92 NG 89 NG 86 91
Oxidation state balancee −1.24 −2.33 −0.21 NG −0.26 NG +0.29 −0.50
a

Cultures were grown on MOD medium containing 30 mM glucose with or without an alternative electron acceptor. Values are means of results for triplicate cultures. For clarity, standard deviations (below 10%) are not shown. WT, wild type (B. cereus F4430/73); fnr, fnr mutant; NG, no growth; ND, not determined; NZ, yield was near zero or below 0.01.

b

Potassium salts of this acid were added to the medium at a final concentration of 20 mM.

c

The biomass yield was calculated (22) with the following approximate molecular formula: molecular mass of C4H7O2N ≈ 100 g/mol.

d

The values were corrected for CO2 fixation related to the formation of succinate (see Fig. 1). The biomass was taken into account as a carbon content of 50%.

e

The oxidation state balance was calculated as the sum of products with positive oxidation states and products with negative oxidation states per mole of consumed glucose. The balance was corrected for CO2 fixation. For more details, see Materials and Methods.