Immobilization of α‐amylase in polyelectrolyte complexes

Abstract

Herein, we report the formation of α‐amylase containing polyelectrolyte complexes (PECs). The method for the encapsulation of α‐amylase is based on interactions between two oppositely charged polyelectrolytes, poly(acrylic acid) (PAA) and polyethylenimine (PEI). We could show that electrostatic interactions ensure the incorporation of the enzyme into the formed polyelectrolyte complexes. The encapsulation has no negative effect on enzyme activity and protects against denaturation of the enzyme initiated by low pH values. The resulting PECs are 150–250 nm in size with narrow size distribution, appear in a spherical shape and are colloidally stable. The complexation of both polyelectrolytes and the immobilization of α‐amylase are investigated using fractionating techniques mainly the analytical ultracentrifugation and asymmetrical‐flow field‐flow fractionation. The formation of PECs represents a simple method for the encapsulation of α‐amylase without the use of organic solvents and requires no additional purifications steps. This one‐step approach, yielding high encapsulation efficiencies, shows the potential as a drug delivery system for sensitive hydrophilic actives in future. α‐amylase is immobilized in polyelectrolyte complexes made of polyethylenimine and poly(acrylic acid). Optimized encapsulation conditions and the resulting polyelectrolyte complexes are investigated via determination of IEP, α‐amylase activity assays, nanoDSC measurements, zeta potential values, dynamic light scattering, microscopy, and fractionating techniques. The encapsulated enzyme is protected against denaturation initiated by low pH values. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45036.

Phosphonium Polyelectrolyte Complexes for the Encapsulation and Slow Release of Ionic Cargo

“…Polyelectrolytes are polymers composed of charged repeating units. Commonly used examples include the salts of poly­(allylamine), , poly­(acrylic acid), , and poly­(styrenesulfonate), , as well as biopolymers such as hyaluronic acid and chitosan . The polymers can have a fixed charge on each repeat unit or can become charged when protonated or deprotonated by acid or base.…”

Enzyme–Polymer Conjugates to Enhance Enzyme Shelf Life in a Liquid Detergent Formulation

“…The assays for determination of enzyme activity consist of tailored substrates and were specific to one enzyme. Laboratory instructions were taken from literature: protease and α‐amylase . The lipase assay was adapted from Palacios et al…”

“…Laboratory instructions were taken from literature: protease [42] and α-amylase. [15,43] The lipase assay was adapted from Palacios et al [44]…”

“…Polymeric nanocarriers, micelles, liposomes, particles, and capsules belong to these aforementioned enzyme stabilization systems. Another strategy for enzyme stabilization is the covalent coupling of an enzyme to an inert, biocompatible, water‐soluble polymer.…”

“…Polymeric nanocarriers, [4][5][6][7] micelles, [8,9] liposomes, [10,11] particles, [12] and capsules [13][14][15] belong to these aforementioned enzyme stabilization systems. Another strategy for enzyme stabilization Yang et al showed that the proteolytic degradation of proteases (subtilisins) regarding conjugated enzymes-subtilisin as well-is decreased and the conjugates had at least three times higher lifetime compared to the native enzyme.…”