Modified silicates and carbon nanotubes for immobilization of lipase from Rhizomucor miehei: Effect of support and immobilization technique on the catalytic performance of the immobilized biocatalysts


ALAGÖZ D., TOPRAK A., YILDIRIM D., TÜKEL S. S. , Lafuente R. F.

ENZYME AND MICROBIAL TECHNOLOGY, vol.144, 2021 (Peer-Reviewed Journal) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 144
  • Publication Date: 2021
  • Doi Number: 10.1016/j.enzmictec.2020.109739
  • Journal Name: ENZYME AND MICROBIAL TECHNOLOGY
  • Journal Indexes: Science Citation Index Expanded, Scopus, Academic Search Premier, Artic & Antarctic Regions, BIOSIS, Biotechnology Research Abstracts, CAB Abstracts, Chemical Abstracts Core, Chimica, Compendex, EMBASE, Environment Index, Food Science & Technology Abstracts, INSPEC, MEDLINE, Veterinary Science Database
  • Keywords: Rhizomucor miehei lipase, Carbon nanotube, Silica, Stabilization, COVALENT IMMOBILIZATION, ENZYME IMMOBILIZATION, PROTEIN IMMOBILIZATION, CHEMICAL-MODIFICATION, IMPROVE BIOCATALYST, MESOPOROUS SILICA, AQUEOUS-SOLUTION, AGAROSE BEADS, CROSS-LINKER, SPACER-ARM

Abstract

Lipase from Rhizomucor miehei (RML) was covalently immobilized on different supports, two silica gels and two carbon nanotube samples, using two different strategies. RML was immobilized on 3-carboxypropyl silica gel (RML@Si-COOH) and multi-wall carbon nanotubes containing carboxylic acid functionalities (RML@MCNT-COOH) using a two-step carbodiimide activation/immobilization reaction. Moreover, the enzyme was also immobilized on 3-aminopropyl silica (RML@Si-Glu) and single-wall carbon nanotubes functionalized with 3-APTES and activated with glutaraldehyde (RML@SCNT-Glu). Before and after RML immobilization, the structurel properties of supports were characterized and compared in detail. After immobilization, the expressed activities were 36.9, 90.2, 16.9, and 26.1 % for RML@Si-COOH, RML@Si-Glu, RML@MCNT-COOH, and RML@SCNT-Glu, respectively. The kinetic parameters of free and immobilized RML samples were determined for three substrates, p-nitrophenyl acetate, p-nitrophenyl butyrate and p-nitrophenyl palmitate, and RML@Si-Glu showed higher catalytic efficiency than the other immobilized RML samples. RML@Si-COOH, RML@Si-Glu, RML@MCNT-COOH, and RML@SCNT-Glu exhibited 5.8, 7.6, 4.2 and 4.6 folds longer half-life values than those of the free enzyme at pH 7.5 and 40 degrees C. Recyclability studies showed that all the immobilized RML biocatalysts retained over 90 % of their initial activities after ten cycles in the hydrolysis of p-nitrophenyl butyrate.