INVESTIGATION OF ENZYMATIC OLIGOMERIZATION OF RUTIN

Abstract

The enzymatic polymerization of rutin catalyzed by laccase from Trametes versicolor was investigated under different operating conditions of temperature, pH, solvent, enzyme and substrate concentrations. The highest weight-average molecular mass ( w M ) was about 3900 g/mol. Highest masses were obtained for lowest pH and temperature set point. The production of oligomers was favored when using a cosolvent with a high dielectric constant. MALDI-TOF analyses showed the presence of rutin oligomers with a polymerization degree of up to 6, resulting from simple bridges between rutin unities. 1 H-NMR analyses showed the presence of C-C or C-O linkages in the structure of oligomers, involving both the sugar and phenolic parts of rutin. Oligomers were characterized by a solubility 4200 times higher than rutin. A molecular modeling study of the hexamer indicated a dense network of H-bonds with water molecules. Fractions enriched with oligomers were obtained by tangential diafiltration. The antioxidant activity of oligomers was shown to decrease with w M ,