Enzymes serve as biocatalysts for innumerable important reactions, however, their application has limitations, which can in many cases be overcome by using appropriate immobilization strategies. Here, a new support for immobilizing enzymes is proposed. This hybrid organic-inorganic support is composed of chitosan—a natural, nontoxic, biodegradable, and edible biopolymer—and sodium polyphosphate as the inorganic component. Lipase B from Candida antarctica (CALB) was immobilized on microspheres by encapsulation using these polymers. The characterization of the composites (by infrared spectroscopy, thermogravimetric analysis, and confocal Raman microscopy) confirmed the hybrid nature of the support, whose external part consisted of polyphosphate and core was composed of chitosan. The immobilized enzyme had the following advantages: possibility of enzyme reuse, easy biocatalyst recovery, increased resistance to variations in temperature (activity declined from 60 °C and the enzyme was inactivated at 80 °C), and increased catalytic activity in the transesterification reactions. The encapsulated enzymes were utilized as biocatalysts for transesterification reactions to produce the compound responsible for the aroma of jasmine.

Enzymes serve as biocatalysts for innumerable important reactions; however, their application has limitations, which could be overcome by using appropriate immobilization strategies. Here, a new support for immobilizing enzymes is proposed. This hybrid organicinorganic support is composed of chitosan-a natural, nontoxic, biodegradable, and edible biopolymer-and sodium polyphosphate, which was the inorganic component. Lipase B from Candida antarctica (CALB) was immobilized in microspheres by encapsulation using these polymers. The characterization of the composites (by infrared spectroscopy, thermogravimetric analysis, and confocal Raman microscopy) confirmed the hybrid nature of the support, whose external part consisted of polyphosphate and core was composed of chitosan. The immobilized enzyme had the following advantages: possibility of enzyme reuse, easy biocatalyst recovery, increased resistance to variations in temperature (activity declined from 60°C and the enzyme was inactivated at 80°C), and increased catalytic activity in the transesterification reactions. The encapsulated enzymes were utilized as biocatalysts for transesterification reactions to produce the compound responsible for the aroma of jasmine.

Resumo.A Química é uma ciência essencialmente experimental e a ausência de um conhecimento prático dificulta a aproximação dos conhecimentos teóricos da realidade dos alunos, tornando assim o processo de ensino-aprendizagem difícil. Diante disso, o trabalho teve como proposta a construção de um modelo molecular a partir de materiais de baixo custo, preferencialmente recicláveis e de fácil acesso, a ser aplicado nas escolas de ensino médio público do município de Ubajara -CE, pertencentes à Coordenadoria Regional de Desenvolvimento da Educação 5 (CREDE) da Secretaria de Educação do Estado. Para confecção do modelo molecular foi utilizado papel higiênico, cola branca, tinta guache, pincel e palitos de cotonete. Ou seja, utilizando materiais de baixo custo, esse trabalho nos possibilitou refletir que é exequível usar meios alternativos para o ensino de Química facilitando desta forma a motivação e a compreensão dos alunos.Palavras-chaves: Modelos. Ensino. Química.Abstract. Chemistry is an essentially experimental science and the absence of practical knowledge makes it difficult to approximate the theoretical knowledge of the students' reality, making the teachinglearning process difficult. Thus, the paper was proposed to build a molecular model from inexpensive materials, preferably recyclable and easily accessible, to be applied in high schools public of the city of Ubajara, in Ceará, belonging to Regional Coordination to Development of Education 5 (CREDE) of the State Education Departament. To make the molecular model was used toilet paper, white glue, gouache paint, brush, swab sticks, pliers and wire. This is using low cost materials, this paper has enabled us to reflect that it is feasible use alternative means of chemistry teaching thus facilitating motivation and understanding of the students.Segundo Galiazzi e Gonçalves (2004) a experimentação motiva e desperta o diálogo na sala de aula e influência positivamente no aumento do interesse em aprender ciências, o que constrói um ambiente adequado para a relação professor aluno. Porém, para que isso ocorra, espera-se que o discente do curso de Quí-Conex. Ci. e Tecnol. Fortaleza/CE, v.12, n. 3, p. 19 -24, dez. 2018 Artigo submetido em 16 fev. 2017 e aceito em 03 ago. 2018