| Popis: |
The present work deals with the preparation and characterization of Zn2Al layered double hydroxides (LDHs) intercalated with chloride and dodecyl sulfate ions and their use as supports for the immobilization of Pseudomonas cepacia lipase (LipPS). LipPS was immobilized on LDH by adsorption, in situ entrapment and delamination entrapment methods. The performance of free and immobilized LipPS in the transesterification of (R,S)-1-phenylethanol was compared. The immobilized derivatives prepared by adsorption gave the highest conversions (c = 50%), with an enantiomeric excess of the product (eep) greater than 99% and a high enantiomeric ratio (E > 200). For immobilization by in situ entrapment (coprecipitation), a conversion of 31.5% and E > 200 were obtained. For immobilization by delamination entrapment, a conversion of 36% and E= 155 were obtained. Although the best results were obtained by adsorption, these results show that the delamination entrapment method can also be used to prepare bioinorganic-enzyme materials based on LDH. Our work therefore increases the range of methods that can be used to immobilize lipases for use in the production of optically pure secondary alcohols. |
