A new Cu Schiff base complex with histidine and glutaraldehyde immobilized on modified iron oxide nanoparticles as a recyclable catalyst for the oxidative homocoupling of terminal alkynes

Support-Activity Relationship in Heterogeneous Catalysis for Biomass Valorization and Fine-Chemicals Production

Heterogeneous catalysts are progressively expanding their field of application, from high-throughput reactions for traditional industrial chemistry with production volumes reaching millions of tons per year, a sector in which they are key players, to more niche applications for the production of fine chemicals. These novel applications require a progressive utilization reduction of fossil feedstocks, in favor of renewable ones. Biomasses are the most accessible source of organic precursors, having as advantage their low cost and even distribution across the globe. Unfortunately, they are intrinsically inhomogeneous in nature and their efficient exploitation requires novel catalysts. In this process, an accurate design of the active phase performing the reaction is important; nevertheless, we are often neglecting the importance of the support in guaranteeing stable performances and improving catalytic activity. This review has the goal of gathering and highlighting the cases in which the supports (either derived or not from biomass wastes) share the worth of performing the catalysis with the active phase, for those reactions involving the synthesis of fine chemicals starting from biomasses as feedstocks.

Various type immobilizations of Isocitrate dehydrogenases enzyme on hyaluronic acid modified magnetic nanoparticles as stable biocatalysts

Magnetic nanoparticles (MNPs) were modified by hyaluronic acid (HA). After the process of functionalization, two different strategies have been used to immobilize isocitrate dehydrogenases (IDH) on MNPs. In the first strategy, cross-linked enzyme aggregates were prepared. For this, firstly hyaluronic acid modified magnetic nanoparticles cross-linked enzyme fine aggregates of isocitrate dehydrogenases (IDH/HA/MNPs-CLEAs) were synthesized, and secondly bovine serum albumin (BSA) as co-feeder was used to synthesize the IDH/BSA/HA/MNPs-CLEAs. In the second strategy, the IDH was effectively immobilized on the HA/MNPs surface. The features of MNPs and its derivatives have been studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM), and zeta potential measurements. The activity and stability of IDH in IDH/HA/MNPs, IDH/HA/MNPs-CLEAs, and IDH/BSA/HA/MNPs-CLEAs were enhanced. Besides, the enzyme immobilized was readily separated via external magnet from the reaction medium and reused many times. The acquired findings indicate that HA/MNPs are a novel binder/support system to IDH, and IDH immobilized on this system can become a very important biocatalyst working with high accuracy and sensitivity for the determination of magnesium in drinking water and other biological solutions.