ObjectiveThis study was conducted to characterize recombinant -l-rhamnosidase from Chloroflexus aurantiacus and apply the enzyme in the production of isoquercitrin from rutin.ResultsThe -l-rhamnosidase from C. aurantiacus was cloned and expressed in Escherichia coli BL21 and purified as a soluble enzyme. -l-rhamnosidase purified from C. aurantiacus has a molecular mass of approximately 105kDa and is predicted to exist as a homodimer with a native enzyme of 200kDa. The purified enzyme exhibited the highest specific activity for rutin among the reported isoquercitrin producing -l-rhamnosidases and was applied in the production of isoquercitrin from rutin. Under the optimised conditions of pH 6.0, 50 degrees C, 0.6UmL(-1) -l-rhamnosidase, and 30mM rutin, -l-rhamnosidase from C. aurantiacus produced 30mM isoquercitrin after 2h with a 100% conversion yield and productivity of 15mMh(-1).ConclusionsWe achieved a high productivity of isoquercitrin from rutin. Moreover, these results suggest that -l-rhamnosidase from C. aurantiacus is an effective isoquercitrin producer.