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Naringinase which was extracted from the fermented broth of Cryptococcus albidus was purified about 42-folds with yield 0.7% by sulfate fractionation and chromatography on Toyopearl HW-60, Fractogel DEAE-650-s, and Sepharose 6B columns. Molecular weight of protein determined by gel filtration and SDS-PAGE was 50 kDa. Naringinase of C. albidus includes high content of the dicarbonic and hydrophobic amino acids. Enzyme contains also carbohydrate component, represented by mannose, galactose, rhamnose, ribose, arabinose, xylose, and glucose. The enzyme was optimally active at pH 5.0 and 60 °C. Naringinase was found to exhibit specificity towards p-nitrophenyl-α-L-rhamnose, p-nitrophenyl-β-D-glucose, naringin, and neohesperidin. Its K m towards naringin was 0.77 mM and the V max was 36 U/mg. Naringinase was inhibited by high concentrations of reaction product—L-rhamnose. Enzyme revealed stability to 20% ethanol and 500 mM glucose in the reaction mixture that makes it possible to forecast its practical use in the food industry in the production of juices and wines.

Response surface methodology was used to optimize the fermentation medium for enhancing naringinase production by Staphylococcus xylosus. The first step of this process involved the individual adjustment and optimization of various medium components at shake flask level. Sources of carbon (sucrose) and nitrogen (sodium nitrate), as well as an inducer (naringin) and pH levels were all found to be the important factors significantly affecting naringinase production. In the second step, a 22 full factorial central composite design was applied to determine the optimal levels of each of the significant variables. A second-order polynomial was derived by multiple regression analysis on the experimental data. Using this methodology, the optimum values for the critical components were obtained as follows: sucrose, 10.0%; sodium nitrate, 10.0%; pH 5.6; biomass concentration, 1.58%; and naringin, 0.50% (w/v), respectively. Under optimal conditions, the experimental naringinase production was 8.45 U/mL. The determination coefficients (R 2) were 0.9908 and 0.9950 for naringinase activity and biomass production, respectively, indicating an adequate degree of reliability in the model.

A synthetic polymer, polyvinyl alcohol (PVA), a cheap and nontoxic synthetic polymer to organism, has been ascribed for biocatalyst immobilization. In this work PVA–alginate beads were developed with thermal, mechanical, and chemical stability to high temperatures (

The stability of the mixed enzyme preparation Naringinase from Penicillium decumbens was studied in dependence of the temperature, the pH value, and the enzyme concentration by means of response surface methodology. Deactivation kinetics by formation of an intermediate state was proposed for fitting deactivation data. Empirical models could then be constructed for prediction of deactivation rate constants, specific activity of intermediate state, and half-life values under different incubation conditions. From this study, it can be concluded that (1) Naringinase is most stable in the pH range of 4.5-5.0, being quite sensitive to lower pHs (3.5) and (2) the glyco-enzyme is a rather thermo-stable enzyme preserving its initial activity for long times when incubated at its optimal pH up to temperatures of 65 degrees C. Enriched alpha-L-rhamnosidase after column treatment and ultrafiltration presented similar deactivation kinetics pattern and half-life values as the unpurified enzyme. Thus, any influence of low molecular weight substances on its deactivation is most probably negligible. The intermediate state of the enzyme may correspond to unfolding and self-digestion of its carbohydrate portion, lowering its activity relative to the initial state. The digestion- and unfolding-grade of this intermediate state may also be controlled by the pH and temperature of incubation.

Naringinase from Penicillium species—containing α-l-rhamnosidase and β-d-glucosidase activity—immobilized on silicate carriers can be used as a mild and effective means to cleave naturally occurring glycosides into their aglycones and sugar components. The procedure was tested with flavonoid-, anthraquinone-, and steroidglycosides. Since the solubility of such compounds is limited in aqueous solutions, a simple batch procedure has been developed to convert solid substrates suspended in only small amounts of buffer to the desired products with high yields.

A highly sensitive and specific enzymatic assay for the quantitative determination of α-L-rhamnosides employing naringinase (an enzyme complex consisting of α-L-rhamnosidase and β-L-glucosidase) andL-rhamnose dehydrogenase is described. The test can be carried out in the presence of other glycosides or sugars and deoxysugars. Even compounds having very low solubility can be assayed by this procedure.

Immobilized naringinase can be converted to a preparation showing only rhamnosidase activity by treatment with 0.1M glycine-NaOH buffer, pH 12. A simple method is described to obtain pure prunin in high yield from naringin with the help of this immobilizate.