Department of Physical Sciences, P.D. Patel Institute of Applied Sciences, Charotar University of Science and Technology (CHARUSAT), Changa 388 421, Gujarat, India.
Department of Biological Sciences, P.D. Patel Institute of Applied Sciences, Charotar University of Science and Technology (CHARUSAT), Changa 388 421, Gujarat, India.
Int J Biol Macromol. 2021 Feb 1;169:228-238. doi: 10.1016/j.ijbiomac.2020.12.101. Epub 2020 Dec 15.
Robust amylases with stability and catalysis at multitude of extremities are the need of an hour. Enzyme immobilization may prove beneficial at commercial scale to achieve such attributes. In the present study, a commercially available amylase was immobilized on graphene oxide (GO) - magnetite (FeO) nanoparticles through covalent bonding. The structural and morphological characterizations were conducted by XRD, SEM and TEM. Further, FTIR and TGA confirmed the interaction between amylase, GO and nanoparticles. The variables, such as concentrations of GO (1.3 mg), FeO (58 μg), and amylase (4.5 mg) were optimized by the response surface methodology using central composite design. High loading capacity of 77.58 μg amylase over 1 μg GO-magnetite nanoparticles was achieved under optimum conditions. Biochemically, the pH optimum remained unaltered, i.e., pH 7, whereas, the alkalitolerance was increased by ~20% in relative activities upon immobilization. The half-life of soluble amylase was 13 h, which enhanced to 20 h upon immobilization in 20 mM phosphate buffer, pH 7 at 50 °C. Besides, the thermodynamic parameters supported the stability trends. The immobilized amylase could be used for 11 subsequent cycles. The mentioned attributes and the dextrose equivalent values during the production of high maltose containing syrup highlighted its commercialization.
具有多种极端稳定性和催化活性的强力淀粉酶是当前的需求。酶固定化在商业规模上可能具有优势，可以实现这些特性。在本研究中，通过共价键将商业可得的淀粉酶固定在氧化石墨烯（GO）-磁铁矿（FeO）纳米粒子上。通过 XRD、SEM 和 TEM 进行了结构和形态特征分析。此外，FTIR 和 TGA 证实了淀粉酶、GO 和纳米粒子之间的相互作用。使用中心复合设计的响应面法优化了 GO（1.3mg）、FeO（58μg）和淀粉酶（4.5mg）的浓度等变量。在最佳条件下，实现了 77.58μg 淀粉酶在 1μg GO-磁铁矿纳米粒子上的高负载能力。在生物化学方面，最适 pH 保持不变，即 pH 7，而固定化后相对活性的耐碱性提高了约 20%。可溶性淀粉酶的半衰期为 13 小时，在 50°C、pH 7 的 20mM 磷酸盐缓冲液中固定化后延长至 20 小时。此外，热力学参数支持稳定性趋势。固定化的淀粉酶可以在 11 个后续循环中使用。在生产高麦芽糖含量糖浆过程中表现出的上述特性和葡萄糖当量值突出了其商业化应用。
