Department of Biochemistry, Universidade Estadual de Maringá, Maringá, Brazil.
Department of Biochemistry, Universidade Estadual de Maringá, Maringá, Brazil; Instituto Federal do Mato Grosso do Sul, Coxim, Brazil.
Int J Biol Macromol. 2018 May;111:1206-1213. doi: 10.1016/j.ijbiomac.2018.01.146. Epub 2018 Feb 19.
In this work, a β-glucosidase of Aspergillus awamori with a molecular weight of 180 kDa was produced in solid-state cultures using a mixture of pineapple crown leaves and wheat bran. Maximum production of the enzyme (820 ± 30 U/g substrate) was obtained after 8 days of culture at 28 °C and initial moisture of 80%. The crude enzyme was efficiently immobilized on glutaraldehyde cross-linked commercial gelatin. Immobilization changed the kinetics of the enzyme, whose behavior could no longer be described by a saturation function of the Michaelis-Menten type. Comparative evaluation of the free and immobilized enzyme showed that the immobilized enzyme was more thermostable and less inhibited by glucose than the free form. In consequence of these properties, the immobilized enzyme was able to hydrolyze cellobiose more extensively. In association with Trichoderma reesei cellulase, the free and immobilized β-glucosidase increased the liberation of glucose from cellulose 3- and 5-fold, respectively. Immobilization of the A. awamori β-glucosidase on glutaraldehyde cross-linked commercial gelatin is an efficient and cheap method allowing the reuse of the enzyme by at least 10 times.
在这项工作中，使用菠萝冠叶和麦麸的混合物，在固态培养中生产出了分子量为 180 kDa 的米曲霉β-葡萄糖苷酶。在 28°C 和初始水分 80%的条件下培养 8 天后，可获得最大酶产量（820±30 U/g 底物）。粗酶有效地固定在戊二醛交联的商业明胶上。固定化改变了酶的动力学，其行为不再能用米氏-门坦型的饱和函数来描述。游离酶和固定化酶的比较评价表明，固定化酶比游离酶具有更高的热稳定性和对葡萄糖的抑制作用更小。因此，固定化酶能够更广泛地水解纤维二糖。与里氏木霉纤维素酶结合使用时，游离和固定化的β-葡萄糖苷酶分别使纤维素释放葡萄糖的效率提高了 3 倍和 5 倍。用戊二醛交联的商业明胶固定化米曲霉β-葡萄糖苷酶是一种有效且廉价的方法，可使酶至少重复使用 10 次。
