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Meso-molding three-dimensionally ordered macroporous alumina: A new platform to immobilize enzymes with high performance

Zhou, Liya, Luo, Xucong, Li, Jiaojiao, Ma, Li, He, Ying, Jiang, Yanjun, Yin, Luyan, Gao, Liya
Biochemical engineering journal 2019 v.146 pp. 60-68
Pseudozyma antarctica, acrylamides, aluminum, aluminum oxide, carboxylic ester hydrolases, composite polymers, confocal laser scanning microscopy, crystals, glutaraldehyde, immobilized enzymes, macropores, nitrile hydratase, palmitic acid, penicillin amidase, polystyrenes, porous media, thermal stability
The meso-molding three-dimensionally ordered macroporous alumina (3DOM/m-Al) was synthesized via a dual-templating approach (polystyrene (PS) colloidal crystals as hard template and triblock copolymer P123 as soft template) with hydrous aluminum isopropoxide as precursor. The obtained 3DOM/m-Al was characterized, and the results showed that 3DOM/m-Al had ordered macropores (ca. 300 nm in diameter) with wormhole-like mesopores, relatively high surface areas (338.1 m2/g), large pore volumes (0.4030 cm3/g) and tunable pore sizes. The amino functionalized 3DOM/m-Al by aminopropyltriethoxysilane (APTES) was activated by glutaraldehyde and used as support for the immobilization of three different commercial enzymes (Lipase B from Candida antarctica (CALB), penicillin G acylase (PGA) and nitrile hydratase (NHase)). The result of confocal laser scanning microscopy (CLSM) indicated that the enzyme was successfully immobilized onto glutaraldehyde-activated NH2-3DOM/m-Al. The effect of the immobilized conditions on the specific activity of enzymes was investigated. Compared with free enzymes, the immobilized enzymes exhibited enhanced thermal stability. The three immobilized enzymes (CALB@NH2-3DOM/m-Al, PGA@NH2-3DOM/m-Al and NHase@NH2-3DOM/m-Al) were applied for the synthesis of palmitic acid, 6-aminopenicillanic acid (6-APA) and acrylamide, respectively. After recycling 10 times, CALB@NH2-3DOM/m-Al, PGA@NH2-3DOM/m-Al and NHase@NH2-3DOM/m-Al retained approximately 76%, 87% and 52% of their initial activities, respectively, indicating that the immobilized enzymes had good operational stability. Therefore, this work documented herein provides a versatile platform for enzyme immobilization with several inherent advantages.