Preparation, Characterization And Application Of New Gel Lens Film Of Loading Permeabilized Brewer's Yeast Cells

In this paper, the main work is that preparation and characterization of polyvinyl alcohol/organophilic montmorilonite(PVA/OMONT) new gel lens film and using this new gel lens film of loading permeabilized brewer's yeast cells as a bocatalyst , and then bioreduction of chiral intermediates of HMG-CoA reductase inhibitors: ethyl(S)-4-chloro-3-hydroxybutanoate ((S)-CHBE)First of all, we investigated preparation, characterization of nanocomposites gel carrier material. The main procedure include: it is obtained OMONT by organically modifying MONT.After OMONT mixing with PVA matrix,the mixture was droped on a smooth polystyrene plate with 7-gauge needle,and then they were induced crystallization by freeze-thawing at -20℃to obtain PVA/OMONT gel lens film.After screening concentration of PVA and optimization of the type of PVA, the results show that 15%PVA possess good mobility,good gelation,high mechanical strength and simple operation .Moreover, we also investigated that when different amounts of OMONT mixed with 15%PVA matrix, the hydrophilic and hydrophobic molecules diffusion in nanocomposite gel lens films.The results showed when containing 15%PVA and 0.1%OMONT, diffusion of hydrophilic and hydrophobic molecules in gel lens films is relatively good,specially, diffusion of hydrophobic molecule in these gel lens films was to be obviously improved.The second, we immobilized cells with this nanocomposite gel matrix by the freezing-thawing method. We investigated the embedding rate of immobilized cells and effects of pH and temperature on intracellular alcohol dehydrogenase (ADH) activity of immobilized cells and storage stability of gel lens films. The experimental results indicate that cell loading is 30% and the embedding rate is up to 90%. In addition, the optimum pH and temperature on ADH activity of the immobilized cells at pH7.0-8.0 and 30℃and the intracellular ADH activity of immobilized cells retained over 81% of it original activity after one month of storage. It can be seen that the immobilized cells gel lens films had good storage stability.Finally, we using the new gel lens film as a biocatalyst to synthesize (S)-CHBE, the yield and the enantiomeric excess (ee) of it reached 88% and 99.1% respectively. Furthermore, this biocatalyst also showed good reusability. The intracellular ADH of immobilized cells retained 88% of its initial activity after 20 cycles.