Immobilization of Naringinase in PVA–Alginate Matrix Using an Innovative Technique

Abstract

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 (<80 degrees C). The combination of alginate and bead treatment with sodium sulfate not only prevented agglomeration but produced beads of high gel strength and conferred enzyme protection from inactivation by boric acid. Naringinase from Penicillium decumbens was immobilized in PVA (10%)-alginate beads with three different sizes (1-3 mm), at three different alginate concentrations (0.2-1.0%), and these features were investigated in terms of swelling ratio within the beads, enzyme activity, and immobilization yield during hydrolysis of naringin. The pH and temperature optimum were 4.0 and 70 degrees C for the PVA-alginate-immobilized naringinase. The highest naringinase activity yield in PVA (10%)-alginate (1%) beads of 2 mm was 80%, at pH 4.0 and 70 degrees C. The Michaelis constant (K(Mapp)) and the maximum reaction velocity (V(maxapp)) were evaluated for both free (K(Mapp) = 0.233 mM; V(maxapp) = 0.13 mM min(-1)) and immobilized naringinase (K(Mapp) = 0.349 mM; V(maxapp) = 0.08 mM min(-1)). The residual activity of the immobilized enzyme was followed in eight consecutive batch runs with a retention activity of 70%. After 6 weeks, upon storage in acetate buffer pH 4 at 4 degrees C, the immobilized biocatalyst retained 90% of the initial activity. These promising results are illustrative of the potential of this immobilization strategy for the system evaluated and suggest that its application may be effectively performed for the entrapment of other biocatalysts.

Immobilization of phospholipase a1 using a polyvinyl alcohol-alginate matrix and evaluation of the effects of immobilization

“…It was also observed that high activity of the immobilized enzyme occurred in a broad pH between 5.2-6.4, which implied that the beads played a protective role for the immobilized enzyme. Similar results were reported for free phospholipase A1 in gelatin hydrogel (Sheelu et al, 2008), free naringinase in PVA matrices (Şekeroğlu et al, 2006;Nunes et al, 2010), laccase in PVA Cryogel Type Carrier (Stanescu et al, 2010) and dextranase in BSA with a cross-linking agent (El-Tanash et al, 2011).…”

“…Increasing the concentration of sodium alginate from 2% to 4%, the immobilized enzyme activity and immobilization yield decreased. The result suggest that the number of hydrogen bonds between polymer chains increased, which led to an increase in the density of physical cross-linking sites (Nunes et al, 2010;El-Din et al, 2007). Table 4 indicated the effects of different concentrations of phospholipase A1 immobilized in PVAalginate beads.…”

“…It was presumed that PVA might contribute to improve the durability and strength of the beads, while sodium alginate might improve the surface properties of the beads, reducing the tendency to agglomeration (Long et al, 2004). PVA-alginate beads have been used as a carrier for immobilized cells and enzymes (Idris et al, 2008;Nunes et al, 2010;Qin et al, 2010;Takei et al, 2011). However, very little literature on PVAalginate beads as an immobilization material of phospholipase A1 is available.…”

“…The preparation conditions such as concentration of matrix (PVA and sodium alginate) and crosslinkage (boric acid and calcium chloride) solution, need to be properly established in order to improve the efficiency of enzyme immobilization, since different preparation conditions could highly affect the immobilized enzyme activity and immobilization yield (Idris et al, 2008;Nunes et al, 2010).…”

Active Packaging Coatings

“…Naringinase activity was maintained for 15 days storage after preparation of the biocatalytic active packaging coating, and kM values were lower when compared to free enzyme. Nunes et al, achieved similar success by cross-linking naringinase to polyvinyl alcohol and alginate using boric acid for de-bittering [72]. In other work, β-galactosidase was bound to amine-functionalized polyethylene films by a dialdehyde tether to reduce milk lactose in package [64].…”