Utilization of Nano-SiO2 as a Supporting Material for Immobilization of Porcine Pancreatic Lipase.

Nano-SiO2 is an inexpensive material for enzyme immobilization and has been frequently utilized for this purpose. In addition to its low cost, Nano-SiO2 has several advantages when used as a supporting material, including its lack of toxicity and chemical reactivity, allowing easy fixation of enzymes. In this article, Porcine Pancreatic lipase was non-covalently immobilized on Nano-SiO2. The properties of immobilized enzyme were then defined. The optimum pH and temperature for the immobilized PPL for hydrolysis of olive oil were determined as 7.6 and 40-50 °C, respectively. The immobilized enzyme possessed high stability in batch operation; with 73.5% of the initial activity still remaining after 8 times of repeated operation of the immobilized lipase. The immobilized enzyme was more stable than free enzyme and t1/2 was 25 d, while free lipase activity was lost 50% in 2 days. The apparent Km for the immobilized enzyme was significantly smaller than that of the free one.

A Comparison of the Resolution of Selective (+/-)-Glycidyl Butyrate by Using Free and Nano-SiO2 Immobilized Porcine Pancreatic Lipase.

To explore the hydrolyzed properties of nano-SiO2 immobilized porcine pancreatic lipase, the selective hydrolysis of immobilized lipase for glycidyl butyrate was compared with the free enzyme. The hydrolysis selectivity of the immobilized biocatalyst was evaluated and compared with the free enzyme using the enantiomeric excess (ee) of resolving racemic glycidyl butyrate as the indicator. The enantiomeric excess of the immobilized biocatalyst could be increased by 4.5%-10.0% which compared with the free enzyme under every single technological condition. The ee was improved from 84.7% for free enzyme to 91.6% for the immobilized enzyme with 61.2% conversion. Compared with free enzyme, the conversion rate of the immobilized enzyme was increased slightly, but the % enantiomeric excess of the immobilized enzyme was increased greatly.

[Optimization of enzymatic resolution technique of glycidyl butyrate via response surface methodology].

Our previous work has indicated that enzymatic resolution of glycidyl butyrate are strongly affected by many factors, including concentration of substrate, amount of lipase, the temperature, pH, shaking speed and reaction time. In this study, Plackett-Burman design was undertaken to evaluate the effects of the six factors. By regression analysis, concentration of substrate, amount of lipase and the temperature were found to be important for enzymatic resolution of glycidyl butyrate. In the second phase of the optimization process, a response surfacemethodology (RSM) was used to optimize the above critical factors, and to find out the optimal concentration levels and the relationships between these factors. By solving the quadratic regression model equation using appropriate statistic methods, the optimal parameter of the variables were determined as: 0.499 mol/L glycidyl butyrate, 30.23 mg/g lipase and 29.68 degrees C. In the optimum condition, the value of enantiomeric excess(ee%) was 93.28%. Compared to 84.65% which was the maximum ee% under the non-optimized condition, this study has a significant advancement. The experimental data under various conditions have validated the theoretical values.