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

• Published in: Enzyme and microbial technology Vol. 39; no. 6; pp. 1205 - 1213
• Main Authors: Morana, Alessandra, Mangione, Anna, Maurelli, Luisa, Fiume, Immacolata, Paris, Ornella, Cannio, Raffaele, Rossi, Mosè
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 03.10.2006; Elsevier Science
• Subjects: Alginate; Biological and medical sciences; Biotechnology; Escherichia coli; Fundamental and applied biological sciences. Psychology; Immobilization; Sulfolobus solfataricus; Xylose; β-Xylosidase; Xylose; Immobilization; β-Xylosidase; Alginate; Enzyme; Alginates; Thermal stability; Biocatalyst; Xylan 1,4-β-xylosidase; Characterization; Glycosidases; Hydrolases; O-Glycosidases
• ISSN: 0141-0229; 1879-0909
• DOI: 10.1016/j.enzmictec.2006.03.010

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.