Fabrication of a magnetic nanoparticle embedded NH-MIL-88B MOF hybrid for highly efficient covalent immobilization of lipase

• Published in: RSC advances 2016-07, Vol.6 (71), p.66385-66393
• Main Authors: Samui, Arpita, Chowdhuri, Angshuman Ray, Mahto, Triveni Kumar, Sahu, Sumanta Kumar
• Format: Article
• ISSN: 2046-2069
• DOI: 10.1039/c6ra10885g

Metal-organic frameworks (MOFs), a class of porous hybrid materials composed of metal ions and organic ligands, have been studied for a variety of applications. In this work, for the first time, magnetic MOFs are developed for lipase immobilization. A general one-step in situ hydrothermal route is developed for the construction of MOFs encapsulating superparamagnetic Fe 3 O 4 nanoparticles. The integration of Fe 3 O 4 nanoparticles into the MOFs exhibits many interesting inherent properties including a porous nature, easy functionalization as well as strong superparamagnetism. Here Candida rugosa lipase (CRL) is covalently attached to amino-rich magnetic MOFs. The resulting magnetic MOFs are characterized by means of field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and vibrating sample magnetometer (VSM) measurements. Then the enzymatic activities of the immobilized CRL are compared with free CRL. The immobilized CRL presented a wider pH tolerance and excellent thermal stability than free CRL. The Michaelis-Menten kinetic constant ( K m ) and maximum reaction velocity ( V max ) for both free and immobilized lipase are investigated. The loading amount of CRL on the magnetic MOFs was 280 mg per g of support and the immobilized CRL was efficiently recycled for up to nine cycles. We demonstrate an approach to synthesize an amine-functionalized magnetic metal-organic framework (MOF) for lipase immobilization. The activity of immobilized lipase is enhanced by different parameters like pH, temperature and thermal stability.