No abstract

No abstract

No abstract

No abstract

No abstract

This research has successfully combined an industrially prominent biocatalyst, CRL, and a biocompatible, environmentally suitable carrier, HAP, into an immobilized preparation with improved catalytic properties. The obtained CRL preparation has excellent potential for the food and flavor industries, major consumers in the global enzyme market. © 2016 Society of Chemical Industry.

Lipase-catalyzed acylation of phloridzin with a wide range of fatty acids and antioxidant activities of synthesized esters were investigated in this study. Polar solvents were suitable reaction media for esterification, and the highest yield was achieved in acetonitrile. By using statistically designed optimization of key experimental factors for the synthesis of phloridzil oleate as the model reaction, great improvements in achieved conversion and yield per enzyme mass were enabled. The most significant progress has been made in the cost-effectiveness of the reaction, since the specific yield of 5.45 mmol g −1 was obtained at 58°C, with 0.09 M phloridzin, 1.17 M oleic acid, and only 0.5% (w/v) biocatalyst. All examined fatty acids were suitable acyl donors, since the chain length and unsaturation degree had slight effects on esterification and all products yielded over 70%. Phloridzil caprate, myristate, and oleate exhibited the highest antioxidant activities among the obtained esters.

α-Glucosidase from S. cerevisiae was covalently immobilized onto Sepabeads EC-EA by the glutaraldehyde method. An analysis of the variables controlling the immobilization process is first presented and it is shown that the highest coupling of α-glucosidase occurred within 24 h. Also, a loading of 30 mg/g support proved to be effective, resulting in a rather high activity of around 45 U g -1 with a satisfactory degree of enzyme fixed. Both free and immobilized enzymes were then characterized by determining the activity profile as a function of pH, temperature and thermal stability. The obtained immobilized preparation showed the same optimum pH, but a higher optimum temperature compared with the soluble one. In addition, the immobilized enzyme treated at 45 ºC for 1 h still retained an activity of around 20 %, whereas the free enzyme completely lost its original activity under this condition. In conclusion, the developed immobilization procedure is quite simple, easily reproducible and provides a promising solution for the application of immobilized α-glucosidase.