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Item type:Publication, Access status: without files , Angle-multiplexed all-dielectric metasurfaces for broadband molecular fingerprint retrieval(American Association for the Advancement of Science (Assoc.), 2019-05-17); 2 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Successful bi-enzyme stabilization for the biomimetic cascade transformation of carbon dioxide(Royal Society of Chemistry (RSC), 2016-07-20); ; ; In nature, carbon dioxide (CO2) conversion to valuable chemicals occurs via several metabolic pathways through multi-enzymatic reactions. Here, we aimed to mimic this by introducing enzyme immobilization in microbead compartments forming a stabilized multi-enzyme system. The system is assembled by encapsulation of phosphoenolpyruvate carboxylase (PEPCase) in branched polymeric microbeads followed by carbonic anhydrase (CA) immobilization on the silica-shell surface of the microbeads. The step-by-step construction of the CA/PEPCase microbeads is monitored based on the stability of each enzyme and cascade enzymatic oxaloacetate (OAA) production rate from a CO2 substrate. Each CA and PEPCase in the microbeads preserved their catalytic activity even after 20 times of reuse, with facile magnetic separability at room temperature. The CA/PEPCase system retained about 75% of the OAA production rate of free CA/PEPCase by forming a multi-enzyme/microbead complex structure. To the best of our knowledge, this report is the first demonstration of a stabilized cascade CA/PEPCase system that mimics the biomimetic CO2 conversion by a multi-enzymatic pathway found in biological systems.Publicationtype: Journal Article119 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , New functional amorphous calcium phosphate nanocomposites by enzyme-assisted biomineralization(American Chemical Society (ACS), 2013-12-31); ; ; In the present study, we report on enzyme-assisted formation of biomineralized amorphous calcium phosphate nanocomposites (ACP-NCs). About 100-200 nm sizes of the spherical porous enzyme-assisted ACP-NCs were successfully synthesized via double reverse microemulsion, but no ACP-NCs formed without the enzyme. It is believed that the enzyme was used as an organic template or additive that could regulate the biomineralization process. The enzyme-assisted ACP-NCs were well characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, dynamic light scattering, and Brunauer-Emmett-Teller (BET) criteria. The BET surface area, total pore volume, pore size from adsorption, and pore size from desorption of the ACP-NCs were 163 m2 g-1 or 0.37 cm3 g -1, 8.87 nm, and 7.48 nm, respectively. The enzyme-assisted ACP-NCs retained about 43% of the catalytic activity of free carboxyl esterase. Furthermore, they preserved their bioactivity even after the 10th reuse and were stable over 10 days even under a stringent shaking conditions. The reported method paves the way for novel biomineralization via enzyme molecules to form functional enzymes containing nanocomposites.Publicationtype: Journal Article98 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Industrial biotechnology in Asia - recent advances in biofuels and biorefineryPublicationtype: Journal Article26 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , CO2 bioconversion using carbonic anhydrase (CA) : effects of PEG rigidity on the structure of bio-mineralized crystal composites(2013-07-09); ; The combined effect of both carbonic anhydrase (CA) and the rigidity of polyethylene glycol (PEG) were found to assist the bio-mineralized crystallization behavior of CO2 differentially. In this study, different forms of magnetically responsive calcium carbonate (CaCO3) crystal composites were successfully formed from gaseous CO2 by using the different forms of polyethylene glycols (PEGs) in a constant CO2 pressure controlled chamber. Polygonal particles were produced with more rigid polymer chains (branched PEG), whereas less rigid polymer chains (PEG) induced the formation of ellipsoidal particles. However, no morphological changes occurred without the presence of CA.Publicationtype: Journal Article53 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Magnetic-separable robust microbeads using a branched polymer for stable enzyme immobilizationUniform magnetic separable robust microbeads using a branched polymer were successfully developed for stable enzyme immobilization. The changed morphology of the microbeads was shown by scanning electron microscopy (SEM) analysis. The aldehyde groups on the polymers and imine groups derived from the Schiff base reaction between the aldehyde and amine moiety were found as the evidence of these reactions based on Fourier transform infrared (FT-IR) spectroscopy. The amine groups of the enzyme react with the aldehyde groups on the glutaraldehyde polymer so that the stable conjugations are formed. The specific activity of the conjugated enzyme was found to be retained more than 50%, but the reaction rate constant, Km value was not changed, compared to the free enzyme. In addition, the enzyme conjugated in the microbeads was found to be highly stable for more than 50 days, pertaining over 60% of its initial activity, even after being reused more than 15 times repeatedly. Furthermore, the magnetic-driven controllability provided facile separable characters for the repeated recycling. It is expected that these microbeads can be utilized as a key tool for successful realization not only in enzymatic conversion processes but also in extended fields; bio-based sensors or analytical devices, bioprocessing, bioremediation, to name only a few of numerous areas.Publicationtype: Journal Article29