Skoronski Everton, Souza Diego Hoefling, Ely Cyntia, Broilo Felipe, Fernandes Mylena, Fúrigo Agenor, Ghislandi Marcos Gomes
Universidade do Estado de Santa Catarina, Departamento de Engenharia Ambiental, Laboratório de Tratamento de Águas e Resíduos, Av. Luís de Camões, 2090, CEP 88520-000, Lages, Santa Catarina, Brazil.
Universidade do Estado de Santa Catarina, Departamento de Engenharia Ambiental, Laboratório de Tratamento de Águas e Resíduos, Av. Luís de Camões, 2090, CEP 88520-000, Lages, Santa Catarina, Brazil.
Int J Biol Macromol. 2017 Jun;99:121-127. doi: 10.1016/j.ijbiomac.2017.02.076. Epub 2017 Feb 22.
Laccase enzymes of Aspergillus oryzae were immobilized on graphene nanosheets by physical adsorption and covalent bonding. Morphological features of the graphene sheets were characterized via microscopy techniques. The immobilization by adsorption was carried out through contact between graphene and solution of laccase enzyme dissolved in deionized water. The adsorption process followed a Freundlich model, showing no tendency to saturation within the range of values used. The process of immobilization by covalent bonding was carried out by nitration of graphene, followed by reduction of sodium borohydride and crosslinking with glutaraldehyde. The process of immobilization by both techniques increased the pH range of activity of the laccase enzyme compared to the free enzyme and increased its operating temperature. On operational stability, the enzyme quickly loses its activity after the second reaction cycle when immobilized via physical adsorption, while the technique by covalent bonding retained around 80% activity after six cycles.
米曲霉的漆酶通过物理吸附和共价键合固定在石墨烯纳米片上。通过显微镜技术对石墨烯片的形态特征进行了表征。吸附固定是通过石墨烯与溶解在去离子水中的漆酶溶液接触来进行的。吸附过程遵循弗伦德里希模型，在所使用的值范围内没有饱和趋势。共价键合固定过程是通过石墨烯的硝化，随后硼氢化钠还原并与戊二醛交联来进行的。与游离酶相比，两种技术的固定过程都增加了漆酶的活性pH范围并提高了其操作温度。在操作稳定性方面，通过物理吸附固定时，酶在第二个反应循环后迅速失去活性，而共价键合技术在六个循环后保留了约80%的活性。
