title: Starch Biocatalyst Based on α-Amylase-Mg/Al-Layered Double Hydroxide Nanohybrids.
abstract: The design of new biocatalysts through the immobilization of enzymes, improving their stability and reuse, plays a major role in the development of sustainable methodologies toward the so-called green chemistry. In this work, α-amylase (AAM) biocatalyst based on Mg3Al-layered double-hydroxide (LDH) matrix was successfully developed with the adsorption method. The adsorption process was studied and optimized as a function of time and enzyme concentration. The biocatalyst was characterized, and the mechanism of interaction between AAM and LDH, as well as the immobilization effects on the catalytic activity, was elucidated. The adsorption process was fast and irreversible, thus yielding a stable biohybrid material. The immobilized AAM partially retained its enzymatic activity, and the biocatalyst rapidly hydrolyzed starch in an aqueous solution with enhanced efficiency at intermediate loading values of ca. 50 mg/g of AAM/LDH. Multiple attachments through electrostatic interactions affected the conformation of the immobilized enzyme on the LDH surface. The biocatalyst was successfully stored in its dry form, retaining 100% of its catalytic activity. The results reveal the potential usefulness of a LDH compound as a support of α-amylase for the hydrolysis of starch that may be applied in industrial and pharmaceutical processes as a simple, environmentally friendly, and low-cost biocatalyst.
authors.affiliation: Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto and ‡Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo , Avenida Bandeirantes 3900, Monte Alegre, 14.040-901 Ribeirão Preto, São Paulo, Brazil.
authors.forename: Felipe
authors.initials: F
authors.lastname: Bruna
authors.affiliation: Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto and ‡Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo , Avenida Bandeirantes 3900, Monte Alegre, 14.040-901 Ribeirão Preto, São Paulo, Brazil.
authors.forename: Marita G
authors.initials: MG
authors.lastname: Pereira
authors.affiliation: Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto and ‡Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo , Avenida Bandeirantes 3900, Monte Alegre, 14.040-901 Ribeirão Preto, São Paulo, Brazil.
authors.forename: Maria de Lourdes T M
authors.initials: Mde L
authors.lastname: Polizeli
authors.affiliation: Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto and ‡Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo , Avenida Bandeirantes 3900, Monte Alegre, 14.040-901 Ribeirão Preto, São Paulo, Brazil.
authors.forename: João B
authors.initials: JB
authors.lastname: Valim
mesh_terms: D000535:Aluminum / Q000737:chemistry; D055162:Biocatalysis; D004591:Electrophoresis, Polyacrylamide Gel; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism; D006868:Hydrolysis; D006878:Hydroxides / Q000737:chemistry*; D008274:Magnesium / Q000737:chemistry; D049329:Nanostructures / Q000737:chemistry*; D013213:Starch / Q000378:metabolism*; D000516:alpha-Amylases / Q000737:chemistry / Q000378:metabolism*
chemical_list: D004800:Enzymes, Immobilized; D006878:Hydroxides; D013213:Starch; C031356:hydroxide ion; D000535:Aluminum; D000516:alpha-Amylases; D008274:Magnesium
keywords: adsorption; biohybrid materials; biomolecules; enzyme immobilization; hydrotalcites; layered double hydroxides; starch converting; α-amylase