ON THE CALCULATION OF THE FREE-ENERGY CHANGE ACCOMPANYING THE GROWTH OF ESCHERICHIA-COLI K-12 ON SUCCINIC ACID

Determinations of the DELTA-G0' accompanying the growth of Escherichia coli K-12 on succinic acid are made using 2 different methods. The DELTA-G0' accompanying catabolism could be calculated directly because the thermodynamic properties of the reactants and products are known. The DELTA-G' accompanying anabolism could not be calculated directly because the DELTA-G(f) value for a unit mass of cells was not known. A description is given of a deduction that the DELTA-G' accompanying anabolism is zero, or nearly so. This is followed by a description of 2 methods, whereby the free energy of formation of a unit quantity of cellular substance can be calculated. The 2 values obtained by these methods are used to calculate the free-energy change accompanying anabolism, the resultant values being 1.72 and -11.68 kJ, respectively, with an average of -4.98 kJ (-1.19 kcal). This value is sufficiently close to zero that it can be considered to be so, indicating that the DELTA-G' accompanying metabolism is that of catabolism alone.