Nanoencapsulated laccases obtained by double-emulsion technique. Effects on enzyme activity ph-dependence and stability

Abstract

One primary drawback of enzyme catalysis at industrial scale is the short-term service life of the enzymes, they lose their activity due to oxidation or other processes which results in less stability and a shorter lifetime thereby rendering them less efficient. An effective way to increase the stability of the enzymes is to attach them to nanoparticles. In this work, the polymer Eudragit® L 100-55 sensitive to pH was used to prepare laccase polymeric nanoparticles by the double-emulsion solvent evaporation approach. The size and morphology of the nanoparticles obtained were evaluated—as well as the encapsulation efficiency and zeta potential. pH effect on activity and stability was compared between free and immobilized laccase. Their stability was also determined in a sequential assay involving acidic pHs up to alkaline ones. The nanoparticles had a spherical shape with a mean size of 147 nm, zeta potential of −22.7 mV at pH 7.0 and load efficiency of 87%. The optimum pH of both free and immobilized laccases was 3.0, being the nanoparticles more stable at acidic pHs. Thus, this would be the first report of obtaining laccase nanoparticles with potential application in animal feed due to the stability conferred to enzymatic activity at pHs similar to those present in the gastrointestinal tract of rabbits, which would allow their potential use in animal feed.