Enzymes nanoencapsulation with

The use of an enzyme in a cascade using nanoencapsulation has also been demonstrated [23]. In this case, the dynamic kinetic resolution (DKR) of secondary alcohols was achieved with an acidic zeolite and an incompatible enzyme, Candida antarctica lipase B (CALB) (Scheme 5.8). 

After each activity measurement, the nanoencapsulated-enzyme samples were transferred with a pipet from the reaction vessel back to a centrifuge tube for reusability analyses. The samples were centrifuge washed, as described earlier, for three times, in 10 mM bis-tris propane, pH 7.2, and the supernatant was decanted and retained for analysis of enzyme leakage. The final washed sample was then stored, decanted dry, in its tube at 6 C until next trial. 

Utilizing the low volume shrinkage process, a total of five samples of nanoencapsulated OPAA were prepared along with control samples. The control samples either lacked the pore-forming agent (template) or the enzyme. Note that data for the control samples are not presented. Table I summarized the physical pore parameters (pore size, surface area, and pore volume) and... 

The protective advantage the matrix has on the enzyme is particularly evidenced in the dimethyl formamide (DMF) samples, as shown in Figure 3. As mentioned above (Figure 2), the free OPAA exhibited the lowest activity in the presence of DMF (88% loss) relative to free OPAA, also in 20% DMF. Once the enzyme was nanoencapsulated, enzyme activity increased by about 40% compared to that of free OPAA, especially in both TMOS and 3MTMS-wet gel samples. Unfortunately, the enzymatic activity in the 3MTMS-F50-OPAA is still very low. Perhaps the polar nature of the DMF solvent which contained the substrate limited its ability to interact with the hydrophobic OPAA nanoencapsulated within the hydrophobic 3MTMS-F50-OPAA. 

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