Enhanced biocatalysis mechanism under microwave irradiation in isoquercitrin production revealed by circular dichroism and surface plasmon resonance spectroscopy

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 degrees C and microwave power density 88.9 W/L. Enzymatic reaction rate and Vm/Km 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. (C) 2016 Elsevier Ltd. All rights reserved.