Biotransformation of rutin to isoquercitrin using recombinant α-l-rhamnosidase from Bifidobacterium breve

Abstract

Objectives

To biotransform rutin into isoquercitrin.

Results

A α-l-rhamnosidase from Bifidobacterium breve was produced by using Escherichia coli BL21 for biotransformation of rutin to isoquercitrin. The enzyme was purified by Ni²⁺-NTA chromatography to yield a soluble protein with a specific activity of 56 U protein mg⁻¹. The maximum enzyme activities were at pH 6.5, 55 °C, 20 mM rutin, and 1.2 U enzyme ml⁻¹. Under optimal conditions, the half-life of the enzyme was 96 h. The K _m and V _max values were 2.2 mM, 56.4 μmol mg⁻¹ min⁻¹ and 2.1 mM, 57.5 μmol mg⁻¹ min⁻¹ using pNP-Rha and rutin as substrates, respectively. The kinetic behavior indicated that the recombinant α-l-rhamnosidase has good catalytic performance for producing isoquercitrin. 20 mM rutin was biotransformed into 18.25 and 19.87 mM isoquercitrin after 60 and 240 min.

Conclusion

The specific biotransformation of rutin to isoquercitrin using recombinant α-l-rhamnosidase from B. breve is a feasible method for use in industrial processes.