Bioinorganic Nanohybrid Catalyst for Multistep Synthesis of Acetaminophen, an Analgesic

Achieving cinnamic acid amides in water by a variant of acyltransferase from Mycobacterium smegmatis and its immobilized form using Ni-NTA modified aspen powder as a carrier

An aqueous N-acylation reaction for preparing cinnamic acid amides was realized by using a variant of acyltransferase from Mycobacterium smegmatis (MsAcT-L12A), whereas the wild-type MsAcT showed no activity. MsAcT-L12A exhibited broad substrate adaptability, and preferred the substrates with electron-donating group. When the vinyl cinnamate (1a, 40 mM) and p-methoxyaniline (2a, 4 mM) were involved in the reaction, the excellent yield reached to 86.7 % ± 2.1 % within 3 h by MsAcT-L12A (1 mgpro./mL) in a PBS buffer (100 mM, pH 8.0) at 25 °C. The aqueous N-acylation reaction could be further improved by using an immobilized MsAcT-L12A. The biomass aspen powder (AP) as a carrier provided a low-cost, green, and environmental-friendly immobilization strategy. After it was modified by Ni-NTA, the obtained Ni-NAP could realize one-step purification and immobilization of MsAcT-L12A. The accomplished MsAcT-L12A-Ni-NAP exhibited excellent stability and recyclability, and retained its relative yield as 83.3 % ± 2.2 % even after the 7th cycle of reuse. Using only PBS buffer as a reaction medium, the operation for MsAcT-L12A-catalyzed acyl transfer was greatly simplified, and the improved stabilities of MsAcT-L12A-Ni-NAP could enhance its application potential.

Protein-supported transition metal catalysts: Preparation, catalytic applications, and prospects

The immobilization of transition metal catalysts onto supports enables their easier recycling and improves catalytic performance. Protein supports not only support and stabilize transition metal catalysts but also enable the incorporation of biocompatibility and enzymatic catalysis into these catalysts. Consequently, the engineering of protein-supported transition metal catalysts (PTMCs) has emerged as an effective approach to improving their catalytic performance and widening their catalytic applications. Here, we review the recent development of the preparation and applications of PTMCs. The preparation of PTMCs will be summarized and discussed in terms of the types of protein supports, including proteins, protein assemblies, protein-polymer conjugates, and cross-linked proteins. Then, their catalytic applications including organic synthesis, photocatalysis, polymerization, and biomedicine, will be surveyed and compared. Meanwhile, the established catalytic structures-function relationships will be summarized. Lastly, the remaining issues and prospects will be discussed. By surveying a wide range of PTMCs, we believe that this review will attract a broad readership and stimulate the development of PTMCs.

Expanding the Synthetic Toolbox through Metal-Enzyme Cascade Reactions

The combination of metal-, photo-, enzyme-, and/or organocatalysis provides multiple synthetic solutions, especially when the creation of chiral centers is involved. Historically, enzymes and transition metal species have been exploited simultaneously through dynamic kinetic resolutions of racemates. However, more recently, linear cascades have appeared as elegant solutions for the preparation of valuable organic molecules combining multiple bioprocesses and metal-catalyzed transformations. Many advantages are derived from this symbiosis, although there are still bottlenecks to be addressed including the successful coexistence of both catalyst types, the need for compatible reaction media and mild conditions, or the minimization of cross-reactivities. Therefore, solutions are here also provided by means of catalyst coimmobilization, compartmentalization strategies, flow chemistry, etc. A comprehensive review is presented focusing on the period 2015 to early 2022, which has been divided into two main sections that comprise first the use of metals and enzymes as independent catalysts but working in an orchestral or sequential manner, and later their application as bionanohybrid materials through their coimmobilization in adequate supports. Each part has been classified into different subheadings, the first part based on the reaction catalyzed by the metal catalyst, while the development of nonasymmetric or stereoselective processes was considered for the bionanohybrid section.

Nanobiohybrids: a new concept for metal nanoparticles synthesis

In recent years, nanoscience and nanotechnology have brought a great revolution in different areas. In particular, the synthesis of transition metal nanoparticles has been of great relevance for their use in areas such as biomedicine, antimicrobial properties or catalytic applications for chemical synthesis. Recently, an innovative straightforward and very efficient synthesis of these nanoparticles by simply using enzymes as inductors in aqueous media has been described. This represents a very green alternative to the different methodologies described in the literature for metal nanoparticles preparation where harsh conditions are necessary. In this review the most recent advances in the synthesis of metal nanoparticles by this green technology, explaining the synthetic mechanism, the role of the enzyme in the formation of the nanoparticles and the effect on the final properties of these nanoparticles, are summarised. The application of these novel metal nanoparticles-enzyme hybrids in synthetic chemistry as heterogeneous catalysts with metal or dual (enzymatic and metallic) activity and their capacity as environmental and antimicrobial agents have also been discussed.

The Influence of Materials, Heterostructure, and Orientation for Nanohybrids on Photocatalytic Activity

In this work, different structures based on electrodeposited n-type ZnO nanorods and p-type Cu₂O, CuSCN, and NiO nanostructures are fabricated for the degradation of methyl orange (MO). The influence of materials, heterostructure, and orientation for nanohybrids on photocatalytic activity is discussed for the first time. The heterojunction structures show remarkable enhancement compared to the bare semiconductor. The morphology of nanostructure has mainly an influence on the photocatalytic activity. NiO has the highest catalytic activity among the four pristine semiconductor nanostructures of ZnO, Cu₂O, CuSCN, and NiO. The greatest enhancement of the photocatalytic activity is obtained using a ZnO/NiO (1 min) heterostructure attributed to the heterojunction structure and extremely higher specific surface area, which can degrade MO (20 mg/L) into colorless within 20 min with the fastest photocatalytic speed among homogeneous heterojunction structures. Meanwhile, the methodology and data analysis described herein will serve as an effective approach for the design of hybrid nanostructures for solar energy application, and the appropriate nanohybrids will have significant potential to solve the environment and energy issues.