How to calculate thermostability of enzymes using a simple approach.

Determination of thermostability of enzymes is of prime importance for their successful industrial applications and, yet, the published data has often been incompletely analyzed to assess the suitability of enzymes. It is possible to determine meaningful thermostability parameters from the routinely acquired data through a straightforward method that is not only more informative but also provides a means to compare thermostability of enzymes from different sources. Here, we describe a simple, effective, and economical way to determine enzyme thermostability. In our opinion, including this method in Biochemistry and Molecular Biology curricula will encourage students to include thermostability analysis in their future work, leading to a more meaningful approach to evaluate and compare enzymes. Furthermore, as the method requires minimum specialized equipment, the analysis will be particularly suitable for labs that cannot afford expensive setup. © 2018 by The International Union of Biochemistry and Molecular Biology, 46:398-402, 2018.

A Thermostable Crude Endoglucanase Produced by Aspergillus fumigatus in a Novel Solid State Fermentation Process Using Isolated Free Water.

Aspergillus fumigatus was grown on chopped wheat straw in a solid state fermentation (SSF) process carried out in constant presence of isolated free water inside the fermentation chamber. The system allowed maintaining a constant vapor pressure inside the fermentor throughout the fermentation process. Crude endoglucanase produced by A. fumigatus under such conditions was more thermostable than previously reported enzymes of the same fungal strain which were produced under different conditions and was also more thermostable than a number of other previously reported endoglucanases as well. Various thermostability parameters were calculated for the crude endoglucanase. Half lives (T(1/2)) of the enzyme were 6930, 866, and 36 min at 60°C, 70°C, and 80°C, respectively. Enthalpies of activation of denaturation (ΔH(D)*) were 254.04, 253.96, and 253.88 K J mole(-1), at 60°C, 70°C and 80°C, respectively, whereas entropies of activation of denaturation (ΔS(D)*) and free energy changes of activation of denaturation (ΔG(D)*) were 406.45, 401.01, and 406.07 J mole(-1) K(-1) and 118.69, 116.41, and 110.53 K J mole(-1) at 60°C, 70°C and 80°C, respectively.