Effects of Water on Enzyme Performance with an Emphasis on the Reactions in Supercritical Fluids |
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Authors: | K Rezaei E Jenab F Temelli |
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Institution: | 1. Department of Food Science and Engineering, Faculty of Biosystem Engineering, The University of Tehran, Karaj, Iran;2. Department of Food Science and Technology, Faculty of Nutritional and Food Science, Shahid Beheshti Medical University, Tehran, Iran;3. Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada |
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Abstract: | ABSTRACTEnzymes require a certain level of water in their structures in order to maintain their natural conformation, allowing them to deliver their full functionality. Furthermore, as a modifier of the solvent, up to a certain level, water can modify the solvent properties such as polarity/polarizability as well as the solubility of the reactants and the products. In addition, depending on the type of the reaction, water can be a substrate (e.g., in hydrolysis) or a product (e.g., in esterolysis) of the enzymatic reaction, influencing the enzyme turnover in different ways. It is found that regardless of the type of reaction, the functionality of enzyme itself is maximum at an optimum level of water, beyond which the enzyme performance is declined due to the loss in enzyme stability. Furthermore, mass transfer limitations caused by pathway blockage and/or by reduced solubilities of the reactants and/or products can also affect the enzyme performance at higher water levels. Controlling water content of ingoing CO2 and substrates as well as precise management of enzyme support and salt hydrates are important strategies to adjust water level in reaction media, especially in supercritical environments. |
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Keywords: | biocatalysis enzyme support esterification hydrolysis lipids salt hydrate supercritical |
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