title: Immobilization of a novel cold active esterase onto Fe3O4∼cellulose nano-composite enhances catalytic properties.
abstract: A novel esterase, EstH was cloned, purified and characterized from the marine bacterium Zunongwangia sp. The purified EstH showed optimum activity at 30°C and pH 8.5 with ∼50% of original activity at 0°C. EstH was stable in high salt conditions (0-4.5M NaCl). To improve the characteristics and explore the possibilities for application, a new immobilization matrix, Fe3O4∼cellulose nano-composite, was prepared and was characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM). Interestingly the optimal temperature of immobilized EstH elevated to 35°C. Compared to its free form, immobilized EstH showed better temperature stability (48.5% compared to 22.40% at 50°C after 30min), prolonged half-life (32h compared to 18h), higher storage stability (∼71% activity compared to ∼40% after 50days of storage), improved pH tolerance (∼73% activity at pH 4 and 10), and, more importantly, reusability (∼50% activity after 8 repetitive cycles of usage). Enzyme kinetics showed an increase in the Vmax (from 35.76 to 51.14μM/min) and Kcat (from 365s(-1) to 520s(-1)) after immobilization. The superior catalytic properties of immobilized EstH suggest its great potential in biotechnology and industrial processes.
authors.affiliation: College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, China; State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China. Electronic address: nayongeb@gmail.com.
authors.forename: Mohammad Asadur
authors.initials: MA
authors.lastname: Rahman
authors.affiliation: College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, China; State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China. Electronic address: eshageb@gmail.com.
authors.forename: Umma
authors.initials: U
authors.lastname: Culsum
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China. Electronic address: ashok.nadda09@gmail.com.
authors.forename: Ashok
authors.initials: A
authors.lastname: Kumar
authors.affiliation: College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, China. Electronic address: zane_gao1986@163.com.
authors.forename: Haofeng
authors.initials: H
authors.lastname: Gao
authors.affiliation: College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, China. Electronic address: hunan@njtech.edu.cn.
authors.forename: Nan
authors.initials: N
authors.lastname: Hu
mesh_terms: D000595:Amino Acid Sequence; D055162:Biocatalysis; D002482:Cellulose / Q000737:chemistry*; D003001:Cloning, Molecular; D003080:Cold Temperature; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004950:Esterases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D041965:Flavobacteriaceae / Q000201:enzymology; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D053761:Nanocomposites / Q000737:chemistry*; D017421:Sequence Analysis
chemical_list: D004800:Enzymes, Immobilized; D058185:Magnetite Nanoparticles; D002482:Cellulose; D004950:Esterases
keywords: Cold active; Immobilization; Nano-composites; Salt tolerance