Thermodynamics of the conversion of aqueous glucose to fructose

Thermodynamics of the hydrolysis reactions of 1,4-β-d-xylobiose, 1,4-β-d-xylotriose, d-cellobiose, and d-maltose

“…These estimates of possible systematic error are combined in quadrature together with the statistical uncertainties in the measured values of K and D r H , expressed as one estimated standard deviation of the mean, to obtain combined standard uncertainties [11] for each result. These combined standard uncertainties are then multiplied by two to arrive at the final results from our experiments: K = (1.46 ± 0.15) Á 10 3 and D r H = (0.12 ± 0.26) kJ Á mol À1 for reaction (1), D r H = À(0.06 ± 0.18) kJ Á mol À1 for reaction (2), and K = (551 ± 34) for reaction (3). These results all pertain to T = 298.15 K. Since all of these reactions involve non-electrolytes in solutions of low ionic strength, the corrections for the adjustment of the measured values to the standard state are assumed to be negligible.…”

“…was used for the analysis of the final solutions. Thus, it was found that the fractions of unreacted substrates ranged from 0.117 to 0.203 for reaction (1) and from 0.098 to 0.106 for reaction (2). This information was used together with the measured reaction enthalpy changes D r H to calculate the standard enthalpy changes D r H .…”

“…Also, advances in chromatographic apparatus allowed us to determine the equilibrium constant for the hydrolysis reaction of D-maltose, a measurement that we were unable to do %20 years ago in an earlier study [2].…”

Improvement and characterization of a hyperthermophilic glucose isomerase from Thermoanaerobacter ethanolicus and its application in production of high fructose corn syrup

“…However, it is confirmed that some GIs of class II from thermophilic bacterium had good thermostability. Therefore, according to the thermodynamic equilibrium of isomerization, the availability of thermostable and thermoactive GIs of class II for 55 % of HFCS production raises the possibility that higher temperature could be used to improve the potential yield of fructose [40]. Currently, screening hyperthermophilic GIs has been a hot issue in production of 55 % HFCS.…”

“…Currently, 55 % of HFCS with better function of sweetness is more popular as compared to 42 % of HFCS [33]. It has been theorized and confirmed that elevated temperature (>85 °C) is required for isomerization by GI to achieve the 55 % of HFCS due to the isomerization reaction equilibrium, which would avoid additional downstream concentration steps [40]. By far, the production of 55 % of HFCS by one step is still not realized because of lack of thermostable GI with high activity [7,14].…”