Immobilization and characterization of a thermostable β-xylosidase to generate a reusable biocatalyst

Institute of Protein Biochemistry, CNR, via P. Castellino 111, 80131 Naples, Italy
Enzyme and Microbial Technology (Impact Factor: 2.97). 10/2006; 39(6):1205-1213. DOI: 10.1016/j.enzmictec.2006.03.010

ABSTRACT The thermostable β-xylosidase from Sulfolobus solfataricus, expressed in Escherichia coli, was immobilized by entrapment into alginate with full recovery of activity and tested for xylose production from xylan hydrolysates. Since the recombinant activity was also cell bound, alginate beads entrapping E. coli whole cells were also prepared. The immobilized preparations exhibited higher thermostability at 90 °C compared to their free counterparts. The half-lives of the immobilized enzyme and cells were 21 and 23 h, respectively, while half of the inactivation was reached after 10 and 11.5 h for free enzyme and whole cells. Interestingly, thermophilicity increased from 85 up to 100 °C and the optimal pH shifted to higher values for immobilized preparations. Results obtained from xylo-oligosaccharides hydrolysis in subsequent batch experiments of recycling, indicated that the immobilized enzyme had good operational stability, retaining 84% of its initial activity after four cycles.Here we report on the immobilization of the β-xylosidase into alginate and its characterization.

Download full-text


Available from: Alessandra Morana, Feb 11, 2014
  • [Show abstract] [Hide abstract]
    ABSTRACT: Earth observation data have become indispensable in social activities. Although Earth observation data are being used for practical purposes to some extent, new applications of satellite data are required to further routine use of data in larger user communities. The Advanced Land Observing Satellite (ALOS) is to respond to this requirement and was developed based on the engineering heritage of the Japanese Earth Resource Satellite-1 (JERS-1) and the Advanced Earth Observing Satellite (ADEOS) and to enhance their land observing capabilities. ALOS is a research and development satellite, which includes high resolution and wide swath optical sensors and synthetic aperture radar with a pointing capability. It is used to demonstrate technologies such as cartography and environmental monitoring
    Geoscience and Remote Sensing Symposium, 2000. Proceedings. IGARSS 2000. IEEE 2000 International; 02/2000
  • Source
    Química Nova 01/2007; 30(5). DOI:10.1590/S0100-40422007000500025 · 0.66 Impact Factor
  • [Show abstract] [Hide abstract]
    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.
    Applied Microbiology and Biotechnology 07/2007; 75(6):1301-7. DOI:10.1007/s00253-007-0955-3 · 3.81 Impact Factor
Show more