Enzymatic de-rhamnosylation of orange peel naringin by α-L-rhamnosidase from Aspergillus terreus MTCC-3374

α-L-rhamnosidases cleaves terminal α-L-rhamnose specifically from a number of natural glycosides. Most of α-L-rhamnosidases reported so far have their pH optima in the acidic pH range. α-L-rhamnosidases with different physicochemical properties are suitable for different applications. Therefore, there is a scientific need to identify different sources of α-L-rhamnosidases with different properties suitable for different applications. The α-L-rhamnosidase has wide occurrence in nature and has been reported from animal tissues, plants, yeasts, fungi and bacteria. In this study we reports α-L-rhamnosidase secreted by Aspergillus terreus MTCC-3374 are potential catalysis in hydrolysis of naringin content present in orange peels. α-L-rhamnosidase from the culture filtrate of a fungal strain, Aspergillus terreus MTCC-3374 has been purified to homogeneity. The procedure involved concentration by ultrafiltration and anion-exchange chromatography on DEAE. The purified enzyme gave 16 fold purification with 30% recovery of the activity correspond a single protein band to molecular mass of 79.0 kDa in SDS-PAGE analysis. The native PAGE analysis of the purified enzyme also gave single protein band confirming the purity of the enzyme preparation. The Km and Vmax value of the enzyme were 1.5 mM and 34.5 µmole/min/mg, respectively, using p-nitrophenyl α-L-rhamnopyranoside as the substrate. The kcat value was 31.03 s-1 giving kcat/Km value of 2.07 ×104 M-1s-1. The pH and temperature optima of the enzyme were 3.5 and 55.0°C, respectively. The purified enzyme preparation successfully hydrolyzed orange peel naringin in to de rhamnosylated product prunin.