Enhanced biocatalysis mechanism under microwave irradiation in isoquercitrin production revealed by circular dichroism and surface plasmon resonance spectroscopy. (April 2016) - Gong, An
Graphical abstract: Highlights: Microwave irradiation was firstly used in enzymatic synthesis of isoquercitrin. Reaction time (10 min) was greatly decreased to one sixty than that in a batch reactor. V m / K m under microwave irradiation was 17.49-fold higher than that in a batch reactor. Secondary structure data of hesperidinase proved the higher affinity to rutin by CD. SPR showed rutin had a higher affinity to hesperidinase under microwave irradiation. Abstract: An efficient and rapid process for isoquercitrin production by hesperidinase-catalyzed hydrolysis of rutin was successfully developed under microwave irradiation detecting the affinity by circular dichroism (CD) and surface plasmon resonance (SPR) spectroscopy. A maximum isoquercitrin yield of 91.5 ± 2.7% was obtained in 10 min with the conditions of 10 g/L hesperidinase, 2 g/L rutin, 30 °C and microwave power density 88.9 W/L. Enzymatic reaction rate and V m / K m in the microwave reactor were 6.34-fold higher than in a continuous flow microreactor and 1.24-fold higher than in a biphasic system. CD and SPR analysis results also showed that hesperidinase has a better selectivity and affinity (3.3-fold than in a batch reactor) to generate isoquercitrin under microwave irradiation. Microwave irradiation greatly improved the reaction efficiency and productivity, leading to a more positive economical assessment. The binding affinity indicates the presence of strong multivalent interactions between rutin and hesperidinase under microwave irradiation.