title: Stable and continuous long-term enzymatic reaction using an enzyme-nanofiber composite.
abstract: This study shows the preparation and application of enzyme-nanofiber composites for long-term stable operation. The enzyme-nanofiber composite was prepared by coating an enzyme aggregate, the esterase from Rhizopus oryzae, on the surface of the nanofibers. After immobilization on the nanofiber, the apparent K ( m ) for the immobilized esterase was 1.48-fold higher than that of the free esterase, with values of 0.98 and 1.35 mM for the free and immobilized enzymes, respectively. It was found that enzyme-nanofiber was very stable, even when the fibers were shaken in glass vials, preserving 80% of the initial activity for 100 days. In addition, the enzyme-nanofiber composite was used repeatedly in 30 cycles of substrate hydrolysis and still remained active. Consequently, the esterase-nanofiber composite was employed within a continuous reactor system to evaluate its use in a long-term and stable continuous substrate hydrolysis reaction. It was found that the production of p-nitrophenol was stable for at least 400 h. This study demonstrates that the enzyme-nanofiber composite can be used in both repeated-batch mode and a continuous mode for a long-term stable operation.
authors.affiliation: Advanced Environmental Monitoring Research Center (ADEMRC), Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea.
authors.forename: Jin Hyung
authors.initials: JH
authors.lastname: Lee
authors.forename: Ee Taek
authors.initials: ET
authors.lastname: Hwang
authors.forename: Byoung Chan
authors.initials: BC
authors.lastname: Kim
authors.forename: Sun-Mi
authors.initials: SM
authors.lastname: Lee
authors.forename: Byoung-In
authors.initials: BI
authors.lastname: Sang
authors.forename: Yong Su
authors.initials: YS
authors.lastname: Choi
authors.forename: Jungbae
authors.initials: J
authors.lastname: Kim
authors.forename: Man Bock
authors.initials: MB
authors.lastname: Gu
mesh_terms: D019149:Bioreactors; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000502:physiology*; D004950:Esterases / Q000502:physiology*; D008298:Maleates; D049329:Nanostructures; D011137:Polystyrenes; D012233:Rhizopus / Q000201:enzymology
chemical_list: D004800:Enzymes, Immobilized; D008298:Maleates; D011137:Polystyrenes; C521900:poly(styrene-co-maleic anhydride); D004950:Esterases