Immobilization of a novel cold active esterase onto Fe3O4∼cellulose nano-composite enhances catalytic properties

A novel esterase, EstH was cloned, purified and characterized from the marine bacterium Zunongwangla sp. The purified EstH showed optimum activity at 30 degrees C and pH 8.5 with similar to 50% of original activity at 0 degrees C. EstH was stable in high salt conditions (0-4.5 M NaCl). To improve the characteristics and explore the possibilities for application, a new immobilization matrix, Fe3O4 similar to 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 degrees C, Compared to its free form, immobilized EstH showed better temperature stability (48.5% compared to 22.40% at 50 degrees C after 30 min), prolonged half-life (32 h compared to 18 h), higher storage stability (similar to 71% activity compared to similar to 40% after 50 days of storage), improved pH tolerance (similar to 73% activity at pH 4 and 10), and, more importantly, reusability (similar to 50% activity after 8 repetitive cycles of usage). Enzyme kinetics showed an increase in the V-max (from 35.76 to 51.14 mu M/min) and K-cat (from 365 s(-1) to 520 s(-1)) after immobilization. The superior catalytic properties of immobilized EstH suggest its great potential in biotechnology and industrial processes. (C) 2016 Elsevier B.V. All rights reserved.