Rhamnose is gaining increasing attention due to its broad substrate specificity and its great potential for enzymatic production of various rare sugars [3]. These L-Rhamnose isomerases are used in the production of rare sugars such as L-spotose, L-mannose, L-talose, D-cellulose, D-allose and L-rhamnulose
Rhamnose can be isolated from Buckthorn (Rhamnus), poison sumac, and plants in the genus Uncaria. Rhamnose is also produced by microalgae belonging to class Bacillariophyceae (diatoms). Rhamnose is commonly bound to other sugars in nature. It is a common glycone component of glycosides from many plants
a crystalline sugar C6H12O5 that occurs usually in the form of a glycoside in many plants and is obtained in the common dextrorotatory l form.
The L-rhamnose isomerase gene (rhi) of Mesorhizobium loti was cloned and expressed in Escherichia coli, and then characterized. The enzyme exhibited activity with respect to various aldoses, including D-allose and L-talose. Application of it in L-talose production from galactitol was achieved by a two-step reaction, indicating that it can be utilized in the large-scale production of L-talose.
