title: Novel immobilization process of a thermophilic catalase: efficient purification by heat treatment and subsequent immobilization at high temperature.
abstract: The main goal of the present work is to investigate a novel process of purification and immobilization of a thermophilic catalase at high temperatures. The catalase, originated from Bacillus sp., was overexpressed in a recombinant Escherichia coli BL21(DE3)/pET28-CATHis and efficiently purified by heat treatment, achieving a threefold purification. The purified catalase was then immobilized onto an epoxy support at different temperatures (25, 40, and 55 °C). The immobilizate obtained at higher temperatures reached its maximum activity in a shorter time than that obtained at lower temperatures. Furthermore, immobilization at higher temperatures required a lower ionic strength than immobilization at lower temperatures. The characteristics of immobilized enzymes prepared at different temperatures were investigated. The high-temperature immobilizate (55 °C) showed the highest thermal stability, followed by the 40 °C immobilizate. And the high-temperature immobilizate (55 °C) had slightly higher operational stability than the 25 °C immobilizate. All of the immobilized catalase preparations showed higher stability than the free enzyme at alkaline pH 10.0, while the alkali resistance of the 25 °C immobilizate was slightly better than that of the 40 and 55 °C immobilizates.
authors.affiliation: School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing, 100083, China.|School of Civil and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China.|Key Laboratory of Educational Ministry for High Efficient Mining and Safety in Metal Mine, University of Science and Technology Beijing, Beijing, 100083, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Xu
authors.affiliation: School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing, 100083, China. luohui@ustb.edu.cn.
authors.forename: Hui
authors.initials: H
authors.lastname: Luo
authors.affiliation: School of Civil and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China.|Key Laboratory of Educational Ministry for High Efficient Mining and Safety in Metal Mine, University of Science and Technology Beijing, Beijing, 100083, China.
authors.forename: Claudia
authors.initials: C
authors.lastname: López
authors.affiliation: School of Civil and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China.|Key Laboratory of Educational Ministry for High Efficient Mining and Safety in Metal Mine, University of Science and Technology Beijing, Beijing, 100083, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Xiao
authors.affiliation: School of Civil and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China. yhchang@ustb.edu.cn.|Key Laboratory of Educational Ministry for High Efficient Mining and Safety in Metal Mine, University of Science and Technology Beijing, Beijing, 100083, China. yhchang@ustb.edu.cn.
authors.forename: Yanhong
authors.initials: Y
authors.lastname: Chang
mesh_terms: D001407:Bacillus / Q000201:enzymology*; D002374:Catalase / Q000737:chemistry* / Q000302:isolation & purification*; D004789:Enzyme Activation; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry* / Q000302:isolation & purification*; D006361:Heating / Q000379:methods*
chemical_list: D004800:Enzymes, Immobilized; D002374:Catalase
keywords: Catalase; Heat treatment; Immobilization; Purification; Thermophiles