Cyanuric chloride functionalized silica nanoparticles for covalent immobilization of lipase

Abstract

BACKGROUND In this work, fumed nano‐silica (FNS) was chemically modified to amino (AFNS) and subsequently to cyanuric chloride (CCAFNS) modified silica and tested for the immobilization of lipase from Candida rugosa (CRL). The effects of the initial enzyme concentration, immobilization time and buffer ionic strength on immobilization were investigated in order to optimize utilization of the support and determine the mechanism of immobilization. The most active preparations were used to examine thermal and operational stability. RESULTS The amount of immobilized enzyme increased with increasing enzyme concentration, achieving loadings of 121.3, 104.8 and 61.2 mg per g of FNS, CCAFNS and AFNS, respectively. Lipase immobilized on CCAFNS carrier in 0.1 mol L−1 buffer expressed the highest lipolytic activity (1320 IU g−1 support), while more stable preparations were obtained in 1 mol L−1 buffer. CONCLUSION Successful modification of silica was confirmed with Fourier transform infrared spectroscopy and thermogravimetric analysis. Activity results showed that, depending on the support, immobilization was governed by different interactions. On FNS and AFNS immobilization was exclusively by adsorption, while on CCAFNS after the initial adsorption lipase molecules reoriented and amino groups of the enzyme formed a covalent bond with the chlorine atom of the modified carrier. Improved thermal and operational stability of lipase immobilized on CCAFNS in 1 mol L−1 buffer led to the conclusion that electrostatic interactions have a great role in the immobilization. © 2014 Society of Chemical Industry

Co‐immobilization of cellulase and glucose oxidase on graphene oxide by covalent bonds: a biocatalytic system for one‐pot conversion of gluconic acid from carboxymethyl cellulose

“…The absorption peaks at 1392 cm −1 , 1644 cm −1 and at 1743 cm −1 correspond to the stretching vibrations of the CN, CO and CO‐NH 2 , respectively. The peaks around 2900 cm −1 can be caused by the symmetric and antisymmetric stretching vibrations of C‐H aliph groups in CEL . The spectrum of GO‐CEL‐E/N‐GA‐GOD shows the band characteristics associated with the amide group, mainly the occurrence of 1658 cm −1 (CO), 3100–3500 cm −1 (NH stretching), 1550–1640 cm −1 (NH bending), 1458 cm −1 (CN stretching) has indicated covalent attachment GOD …”

“…The peaks around 2900 cm −1 can be caused by the symmetric and antisymmetric stretching vibrations of C-H aliph groups in CEL. [26][27][28] The spectrum of GO-CEL-E/N-GA-GOD shows the band characteristics associated with the amide group, mainly the occurrence of 1658 cm −1 (C O), 3100-3500 cm −1 (N-H stretching), 1550-1640 cm −1 (N-H bending), 1458 cm −1 (C-N stretching) has indicated covalent attachment GOD. 29,30 The morphology of the GO sample was characterized using AFM ( Fig.…”

Epoxy-silanization - tool for improvement of silica nanoparticles as support for lipase immobilization with respect to esterification activity

“…Cyanuric chloride functionalized amino silica (CCAFNS) was prepared as follows: 300 mg of FNS was stirred with 1.18 mL of APTMS, and the AFNS (amino modified fumed nano‐silica) obtained was treated with 1.5 g of CC. The detailed procedure was described previously …”

“…The material obtained after the modification process with GOPTMS is rich in epoxy groups, which are very reactive towards amine, hydroxyl or thiol groups of lipase and as a result covalent bonds between lipase and epoxy groups can be formed. The efficiency of lipase immobilized on epoxy functionalized FNS (GFNS) was evaluated by comparing its activity and thermal stability with cyanuric chloride functionalized amino silica (CCAFNS), which has been recognized as a valuable FNS‐based carrier providing covalent immobilization of lipase …”

Wastewater remediation via combo-technology

“…Further, the enzyme can be positioned accurately onto nanosized magnetic particles with the help of magnetic resonance imaging. Water-treating enzymes immobilized onto silica nanoparticles are lipase, peroxidase, α-amylase, and keratinase; while sensing and monitoring enzymes immobilized onto silica nanoparticles are catalase and glucose oxidase [122][123][124][125]. Generally, magnetic nanoparticles like FeO and Fe 2 O 3 are used for enzyme immobilization due to size uniformity and excellent electrical, optical, magnetic, and chemical properties.…”