Glutaraldehyde activation of polymer Nylon-6 for lipase immobilization: enzyme characteristics and stability.
ABSTRACT An extracellular alkaline lipase of a thermo tolerant Bacillus coagulans BTS-3 was immobilized onto glutaraldehyde activated Nylon-6 by covalent binding. Under optimum conditions, the immobilization yielded a protein loading of 228 microg/g of Nylon-6. Immobilized enzyme showed maximum activity at a temperature of 55 degrees C and pH 7.5. The enzyme was stable between pH 7.5-9.5. It retained 88% of its original activity at 55 degrees C for 2h and also retained 85% of its original activity after eight cycles of hydrolysis of p-NPP. Kinetic parameters Km and Vmax were found to be 4mM and 10 micromol/min/ml, respectively. The influence of organic solvents on the catalytic activity of immobilized enzyme was also evaluated. The bound lipase showed enhanced activity when exposed to n-heptane. The substrate specificity of immobilized enzyme revealed more efficient hydrolysis of higher carbon length (C-16) ester than other ones.
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ABSTRACT: Nylon 6 capillary‐channeled polymer (C‐CP) fibers used as the stationary phase in high‐performance liquid chromatography protein separations have been investigated. A difference in chromatographic behavior between two (presumably identical) nylon 6 C‐CP fibers, designated simply as nylon 6A and nylon 6B, reveals unknown differences in their chemical and physical nature as proteins are less retained on the latter. The possible differences are evaluated through several test methods, including Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), mechanical testing, MALDI‐TOF mass spectrometry, an organic reaction with ninhydrin, and dilute solution viscometry. Nylon 6B is shown to be a larger perimeter, stronger fiber, yet in a 200 mm, 0.8 mm i.d. column having an interstitial fraction of ∼0.6, it has an available surface area of ∼189 cm2, while nylon 6A is almost double that at ∼374 cm2. It is revealed that when in amorphous form, the base polymers have very comparable FTIR and DSC characteristics. When in their solid, extruded fiber form there are significant differences found in crystallinity, tensile strength, molecular weight distribution, and end group density. Nylon 6A is a lower molecular weight fiber, which results in ∼1.3× more amine end groups than nylon 6B. It is the end group density that ultimately determines the separation qualities. These results imply that both a difference in base nylon 6 molecular weight and also the fiber extrusion process have a significant influence on the performance of nylon 6 C‐CP fiber separation of proteins via ion exchange chromatography. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013Journal of Applied Polymer Science 04/2013; 128(2). · 1.64 Impact Factor
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ABSTRACT: The graphite nanosheets decorated with Fe3O4 nanoparticles (about 15–20 nm), i.e., Fe3O4@graphite nanosheets, have been prepared via a facile one-pot method. The resulting composites with large specific surface area, high affinity, and rapid magnetic response were characterized by means of Fourier transform infrared spectra, Raman spectra, powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, elemental analysis, and thermogravimetric analysis, which indicated that the Fe3O4 nanoparticles were chemically integrated on the graphite nanosheets. The porcine pancreatic lipase (PPL) was immobilized onto the Fe3O4@graphite nanosheets through covalent bonding using glutaraldehyde as a coupling reagent, and the properties of the resulting immobilized PPL such as enzymatic activity, stability, and reusability were researched at the same time. The result proved that the immobilized PPL displayed excellent properties and demonstrated that the prepared Fe3O4@graphite nanosheets would present a potential application as a novel carrier for enzyme immobilization, enrichment, and separation.Journal of Nanoparticle Research 06/2014; 16(6). · 2.28 Impact Factor
- PROCESS BIOCHEMISTRY 05/2013; 48(5-6):819-830. · 2.52 Impact Factor