Chemoenzymatic Synthesis of Nitrogen Polymers with Biomedical Applications Catalyzed by Lipases

The application of Candida antarctica lipase B as catalyst in the synthesis of two examples of nitrogen polymers is described. Firstly, we report anovel linear polyamidoamine oligomer, obtained by polymerization of ethyl acrylate and N-methyl-1,3-diaminopropane, catalyzed by Candida antarctica lipase B immobilized on polypropylene. The second part of the chapter describes an efficient route for the synthesis of a novel β-peptoid oligomer with hydroxyalkyl pendant groups in the nitrogen atom, through the polymerization of ethyl N-(2-hydroxyethyl)-β-alaninate catalyzed by Candida antarctica lipase B physically adsorbed within a macroporous poly(methyl methacrylate-co-butyl methacrylate) resin.Moreover,two derivatives of the β-peptoid oligomer were prepared: by acetylation and by grafting polycaprolactone. This last process was performed through ring opening polymerization of caprolactone from the β-peptoid pendant hydroxyl groups and afforded a brush copolymer. The products were blended with polycaprolactone to make films by solvent casting. The inclusion of the acyl derivatives of the β-peptoid to polycaprolactone affected the morphology of the film yielding micro- and nanostructured patterns.The obtained products showed biomedical applications.Fil: Baldessari, Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad de Microanálisis y Métodos Físicos en Química Orgánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Unidad de Microanálisis y Métodos Físicos en Química Orgánica; ArgentinaFil: Garcia Liñares, Guadalupe Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad de Microanálisis y Métodos Físicos en Química Orgánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Unidad de Microanálisis y Métodos Físicos en Química Orgánica; Argentin

Design and characterization of alcalase-chitosan conjugates as potential biocatalysts

In this study, alcalase (protease from Bacillus licheniformis) immobilization by adsorption, enzyme crosslinking and covalent enzyme binding to activated chitosan microbeads were examined. The biocatalysts highest activity was obtained by covalent immobilization of alcalase onto a solid support. The alcalase covalent immobilization onto different types of chitosan beads obtained by inverse emulsion technique and electrostatic extrusion was studied. Parameters examined under different conditions were beads diameter, enzyme loading, enzyme capacity yield, and biocatalyst activity. The highest activity and enzyme loading of 23.6 IU/mg protein and 340.2 mg/g, respectively, were achieved by the enzyme immobilized onto chitosan microbeads obtained by the electrostatic extrusion technique. FT-IR analysis was used to confirm formation of alcalase-chitosan conjugates. The activity of optimally produced alcalase-chitosan microbeads was then verified in the industrially feasible reaction systems of egg white and soy protein hydrolysis. The high degree of hydrolysis of 29.85 +/- 0.967% after 180 min and five successive reuses obtained under real conditions (50 A degrees C, pH 8) verified the covalently bound alcalase to chitosan beads a promising candidate for use in industrial egg white protein hydrolysis process