Immobilization of pectinase on chitosan-magnetic particles: Influence of particle preparation protocol on enzyme properties for fruit juice clarification

[EN] Magnetic-chitosan particles were prepared following three different protocols enabling the preparation of particles with different sizes – nano (Nano-CMag, Micro (Micro-CMag) and Macro (Macro-CMag) – and used for pectinase immobilization and clarification of grape, apple and orange juices. The particle size had a great effect in the kinetic parameters, Nano-CMag biocatalyst presented the highest V value (78.95 mg. min), followed by Micro-CMag and Macro-CMag, with V of 57.20 mg.min and 46.03 mg.min, respectively. However, the highest thermal stability was achieved using Macro-CMag, that was 8 and 3-times more stable than Nano-CMag and Micro-CMag biocatalysts, respectively. Pectinase immobilized on Macro-CMag kept 85% of its initial activity after 25 batch cycles in orange juice clarification. These results suggested that the chitosan magnetic biocatalysts presented great potential application as clarifying catalysts for the fruit juice industry and the great importance of the chitosan particles preparation on the final biocatalyst properties.This work was supported by grants and scholarships (L Dal Magro) from Capes, CNPq (process 403505/2013-5) and FAPERGS (process 17/2551-0000939-8). We gratefully recognize the support from the MINECO from Spanish Government, (project number CTQ2017-86170-R) The authors wish to thank Mr. Ramiro Martínez (Novozymes, Spain), Amazon group and LNF Latinoamericana for kindly supplying the enzymes used in this research, as well as Vitivinicola Jolimont (Canela, Brazil) for providing the grape juice

Chitosan with modified porosity and crosslinked with genipin: A dynamic system structurally characterized

In this work, a deep structural characterization of the chitosan-genipin complex was performed by techniques like small-angle X-ray scattering, dye absorption, atomic force microscopy, compression strength, nitrogen adsorption/desorption, scanning electronic microscopy, and thermogravimetric analysis to understand the changes in the structure through all steps of the process. For this, chitosan beads were modified with Na2CO3 to change porosity and then crosslinked with genipin. The prepared particles were used as support for enzyme immobilization. Our results demonstrated modification in the porosity of the chitosan beads, changing the number of pores and pore volume. After crosslinking process (pH 9), especially the microstructure of chitosan-genipin beads was modified, enhancing the fractality and, after enzyme immobilization (pH 4.5) the fractality increased at the higher scale (∼100 nm) and reduced at the lower scale (∼1–10 nm). β-galactosidase immobilized on the modified particles presented high stability on the continuous production of galactooligosaccharides for 30 days. Our results indicate that the chitosan-genipin complex can be characterized as a plastic and dynamic system due to its structural modifications, particularly in response to changes in the pH environment, even after the crosslinking process.Fil: Esparza Flores, Elí Emanuel. Universidade Federal do Rio Grande do Sul; BrasilFil: Bertoldo Siquiera, Larissa. Universidade Federal do Rio Grande do Sul; BrasilFil: Dias Cardoso, Fernanda. Universidade Federal do Rio Grande do Sul; BrasilFil: Costa, Tania Haas. Universidade Federal do Rio Grande do Sul; BrasilFil: Benvenutti, Edilson Valmir. Universidade Federal do Rio Grande do Sul; BrasilFil: Medina Ramírez, Iliana E.. Universidad Autónoma de Aguascalientes; MéxicoFil: Perullini, Ana Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Inorgánica, Analítica y Química Física; ArgentinaFil: Santagapita, Patricio Roman. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Inorgánica, Analítica y Química Física; ArgentinaFil: Rodrigues, Rafael C.. Universidade Federal do Rio Grande do Sul; BrasilFil: Hertz, Plinho F.. Universidade Federal do Rio Grande do Sul; Brasi

Effect of the Support Size on the Properties of β-Galactosidase Immobilized on Chitosan: Advantages and Disadvantages of Macro and Nanoparticles

The effect of the support size on the properties of enzyme immobilization was investigated by using chitosan macroparticles and nanoparticles. They were prepared by precipitation and ionotropic gelation, respectively, and were characterized by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), transmission electron microscopy (TEM), light scattering analysis (LSA), and N₂ adsorption–desorption isotherms. β-Galactosidase was used as a model enzyme. It was found that the different sizes and porosities of the particles modify the enzymatic load, activity, and thermal stability of the immobilized biocatalysts. The highest activity was shown by the enzyme immobilized on nanoparticles when 204.2 mg protein·(g dry support)⁻¹ were attached. On the other hand, the same biocatalysts presented lower thermal stability than macroparticles. β-Galactosidase immobilized on chitosan macro and nanoparticles exhibited excellent operational stability at 37 °C, because it was still able to hydrolyze 83.2 and 75.93% of lactose, respectively, after 50 cycles of reuse