Spacer arm of ionic liquids facilitated laccase immobilization on magnetic graphene enhancing its stability and catalytic performance

To fulfill the requirements of environmental protection, a magnetically recoverable immobilized laccase has been developed for water pollutant treatment. In order to accomplish this objective, we propose a polydopamine-coated magnetic graphene material that addresses the challenges associated with accumulation caused by electrostatic interactions between graphene and enzyme molecules, which can lead to protein denaturation and inactivation. To achieve this, we present a polydopamine-coated magnetic graphene material that binds to the enzyme molecule through flexible spacer arms formed by ionic liquids. The immobilized laccase exhibited a good protective effect on laccase and showed a high stability and recycling ability. Laccase-ILs-PDA-MGO has a wider pH and temperature range and retains about 80% of its initial activity even after incubation at 50 °C for 2 h, which is 2.2 times more active than free laccase. Furthermore, the laccase-ILs-PDA-MGO exhibited a remarkable removal efficiency of 97.0% and 83.9% toward 2,4-DCP and BPA within 12 h at room temperature. More importantly, laccase-ILs-PDA-MGO can be recovered from the effluent and used multiple times for organic pollutant removal, while maintaining a relative removal efficiency of 80.6% for 2,4-DCP and 81.4% for BPA after undergoing seven cycles. In this study, a strategy for laccase immobilization by utilizing ILs spacer arms to modify GO aims to provide valuable insights into the advancement of efficient enzyme immobilization techniques and the practical application of immobilized enzymes in wastewater treatment.

An efficient approach for the green synthesis of biologically active 2,3-dihydroquinazolin-4(1H)-ones using a magnetic EDTA coated copper based nanocomposite

2,3-Dihydroquinazolinone derivatives are known for antiviral, antimicrobial, analgesic, anti-inflammatory, and anticancer activities. However, recent approaches used for their synthesis suffer from various drawbacks. Therefore, we have fabricated a highly efficient magnetic EDTA-coated catalyst, Fe₃O₄@EDTA/CuI via a simple approach. The ethylenediamine tetraacetic acid (EDTA) plays a crucial role by strongly trapping the catalytic sites of CuI nanoparticles on the surface of the Fe₃O₄ core. The designed nanocatalyst demonstrates its potential for the catalytic synthesis of 2,3-dihydroquinazolinones using 2-aminobenzamide with aldehydes as the reaction partners. The nanocatalyst was thoroughly characterized through X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), vibrating sample magnetometry (VSM), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma analysis (ICP). The physiochemically characterized nanocatalyst was tested for synthesis of 2,3-dihydroquinazolinones and higher yields of derivatives were obtained with less time duration. Moreover, the catalytic synthesis is easy to operate without the use of any kind of additives/bases. Furthermore, the catalyst was magnetically recoverable after the completion of the reaction and displayed reusability for six successive rounds without any loss in its catalytic efficiency (confirmed by XRD, SEM, and TEM of the recycled material) along with very low leaching of copper (2.12 ppm) and iron (0.06 ppm) ions. Also, the green metrics were found in correlation with the ideal values (such as E factor (0.10), process mass intensity (1.10), carbon efficiency (96%) and reaction mass efficiency (90.62%)).