Hydrolysis of citrus peel naringin by recombinant α-L-rhamnosidase from Clostridium stercorarium

The citrus fruit processing industry generates substantial quantities of waste rich in glycosylated phenolic substances such as naringin, which are a valuable natural source of polyphenols as well as L-rhamnopyranose. Naringin is the major polyphenol in bitter orange peel and its hydrolysis by alpha-L-rhamnosidase (EC 3.2.1.40) catalyzes the cleavage of the terminal rhamnosyl groups to form prunin and rhamnose. In this work, a recombinant alpha-L-rhamnosidase from C. stercorarium was shown to be suitable for narigin hydrolysis. The recombinant rhamnosidase was found to be relatively stable at 60 degrees C, and a residual activity close to 50% after 180 min of incubation was demonstrated. The purified enzyme established hydrolysis of naringin extracted from citrus peel waste (CPW). The result indicated that recombinant alpha-L-rhamnosidase has industrial applicability and is an interesting candidate for producing rhamnose from citrus peel. (C) 2010 Society of Chemical Industry