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Enzymes salt hydrate pairs

Zacharis, E., Omar, I.C., Partridge, J. and Robb, D.A. (1997) Selection of salt hydrate pairs for use in water control in enzyme catalysis in organic solvents. Biotechnol. [Pg.364]

Berberich lA, Kaar IL, Russell Al (2003) Use of salt hydrate pairs to control water activity for enzyme catalysis in ionic liquids. Biotechnol Prog 19 1029-1032... [Pg.186]

Berberich et al. used salt hydrate pairs to control water activity in [BMIM][PF6]. The results were in good agreement with that obtained for water activity control using saturated salt solutions. The advantage of pre-equilibration is that the contact of the enzyme with the used salt and thus enzyme deactivation can be avoided. On the other hand it is only applicable for initial rate measurements. This disadvantage can be overcome by controlling water activity with salt hydrate pairs. Berberich et al. measured initial rate - water activities for the transesterification reaction of methyl methacrylate with 2-ethylhexanol in either hexane or [BMIM][PF6]. Both reaction systems gave similar profiles [72],... [Pg.654]

An alternative method for water activity control is based on the fact that salt hydrates containing different numbers of water molecules are interconverted at fixed water activities [15]. The first salt hydrate used was Na2C03- 10H2O. This is converted to Na2C03-7H20 at a water activity of 0.74 at 24 °C. The salt hydrates act as a buffer of the water activity. As long as both salt hydrates are present, the water activity remains at 0.74. If another water activity is desired, another pair of salt hydrates should be chosen. The salt hydrates can be added directly to the organic reaction mixture. One should be careful that the salt hydrates do not interfere with the enzyme or the enzymatic reaction. [Pg.5]

The water activity of pre-equilibrated substrates and enzymes may change when they are put in contact with the SCF for example, SCCO2 may take up water from the enzyme. Furthermore, if water is consumed or produced in the reaction, the water activity of the reaction system will change. Putting salt hydrates in contact with the reaction mixture should buffer the water activity. Suitable pairs of solid salt hydrates may be used to control the water activity more accurately. Examples of salt hydrates and saturated solutions are given in Table 4.9-5. [Pg.431]


See other pages where Enzymes salt hydrate pairs is mentioned: [Pg.207]    [Pg.284]    [Pg.935]    [Pg.936]    [Pg.274]   
See also in sourсe #XX -- [ Pg.206 ]




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