Synthesis of Ag/CuS doped mineral magnetite nanocomposite with improved photocatalytic activity against tetracycline and diclofenac pollutants

The contamination of water sources by pharmaceutical pollutants presents significant environmental and health hazards, making the development of effective photocatalytic materials crucial for their removal. This research focuses on the synthesis of a novel Ag/CuS/Fe₃O₄ nanocomposite and its photocatalytic efficiency against tetracycline (TC) and diclofenac contaminants. The nanocomposite was created through a straightforward and scalable precipitation method, integrating silver nanoparticles (AgNPs) and copper sulfide (CuS) into a magnetite framework. Various analytical techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR),ultraviolet-visible spectrophotometry (UV-Vis) and energy-dispersive X-ray spectroscopy (EDS), were employed to characterize the structural and morphological properties of the synthesized material. The photocatalytic activity was tested by degrading tetracycline and diclofenac under visible light. Results indicated a marked improvement in the photocatalytic performance of the Ag/CuS/Fe₃O₄ nanocomposite (98%photodegradation of TC 60 ppm in 30 min) compared to both pure magnetite and CuS/Fe₃O₄. The enhanced photocatalytic efficiency is attributed to the synergistic interaction between AgNPs, CuS, and Fe3O4, which improves light absorption and charge separation, thereby increasing the generation of reactive oxygen species (ROS) and promoting the degradation of the pollutants. The rate constant k of photodegradation was about 0.1 min-1 for catalyst dosages 0.02 g. Also the effect of photocatalyst dose and concentration of TC and pH of solution was tested. The modified photocatalyst was also used for simultaneous photodegradation of TC and diclofenac successfully. This study highlights the potential of the Ag/CuS/Fe₃O₄ nanocomposite as an efficient and reusable photocatalyst for eliminating pharmaceutical pollutants from water.

Influence of deep eutectic solvents on redox biocatalysis involving alcohol dehydrogenases

Redox biocatalysis plays an increasingly important role in modern organic synthesis. The recent integration of novel media such as deep eutectic solvents (DESs) has significantly impacted this field of chemical biology. Alcohol dehydrogenases (ADHs) are important biocatalysts where their unique specificity is used for enantioselective synthesis. This review explores aspects of redox biocatalysis in the presence of DES both with whole cells and with isolated ADHs. In both cases, the presence of DES has a significant influence on the outcome of reactions albeit via different mechanisms. For whole cells, DES was shown to be a useful tool to direct product formation or configuration - a process of solvent engineering. Whole cells can tolerate DES as media components for the solubilization of hydrophobic substrates. In some cases, DES in the growth medium altered the enantioselectivity of whole cell transformations by solvent control. For isolated enzymes, on the other hand, the presence of DES promotes substrate solubility as well as enhancing enzyme stability and activity. DES can be employed as a smart solvent or smart cosubstrate particularly for cofactor regeneration purposes. From the literatures examined, it is suggested that DES based on choline chloride (ChCl) such as ChCl:Glycerol (Gly), ChCl:Glucose (Glu), and ChCl:1,4-butanediol (1,4-BD) are useful starting points for ADH-based redox biocatalysis. However, each specific reaction will require optimisation due to the influence of several factors on biocatalysis in DES. These include solvent composition, enzyme source, temperature, pH and ionic strength as well as the substrates and products under investigation.

How Can Deep Eutectic Systems Promote Greener Processes in Medicinal Chemistry and Drug Discovery?

Chemists in the medicinal chemistry field are constantly searching for alternatives towards more sustainable and eco-friendly processes for the design and synthesis of drug candidates. The pharmaceutical industry is one of the most polluting industries, having a high E-factor, which is driving the adoption of more sustainable processes not only for new drug candidates, but also in the production of well-established active pharmaceutical ingredients. Deep eutectic systems (DESs) have emerged as a greener alternative to ionic liquids, and their potential to substitute traditional organic solvents in drug discovery has raised interest among scientists. With the use of DESs as alternative solvents, the processes become more attractive in terms of eco-friendliness and recyclability. Furthermore, they might be more effective through making the process simpler, faster, and with maximum efficiency. This review will be focused on the role and application of deep eutectic systems in drug discovery, using biocatalytic processes and traditional organic chemical reactions, as new environmentally benign alternative solvents. Furthermore, herein we also show that DESs, if used in the pharmaceutical industry, may have a significant effect on lowering production costs and decreasing the impact of this industry on the quality of the environment.

Electrochemical Evaluation of Tyrosinase Enzymatic Activity in Deep Eutectic Solvent and Aqueous Deep Eutectic Solvent

The use of green, inexpensive, and biodegradable deep eutectic solvents as nonaqueous solvents and electrolytes could be a useful way to potentially improve the enzyme biosensor performance as well as a profitable strategy to extend their use in the gas phase. However, enzyme activity in these media, although fundamental for their implementation in electrochemical analysis, is still almost unexplored. In this study, an electrochemical approach was employed to monitor tyrosinase enzyme activity in a deep eutectic solvent. This study was performed in a DES consisting of choline chloride (ChCl) as a hydrogen bond acceptor (HBA) and glycerol as a hydrogen bond donor (HBD), while phenol was chosen as the prototype analyte. The tyrosinase enzyme was immobilized on a gold-nanoparticle-modified screen-printed carbon electrode, and its activity was monitored following the reduction current of orthoquinone produced by the tyrosinase biocatalysis of phenol. This work represents a first step toward the realization of green electrochemical biosensors capable of operating in both nonaqueous and gaseous media for the chemical analysis of phenols.

Combination of Enzymes and Deep Eutectic Solvents as Powerful Toolbox for Organic Synthesis

During the last decade, a wide spectrum of applications and advantages in the use of deep eutectic solvents for promoting organic reactions has been well established among the scientific community. Among these synthetic methodologies, in recent years, various examples of biocatalyzed processes have been reported, making use of eutectic mixtures as reaction media, as an improvement in terms of selectivity and sustainability. This review aims to show the newly reported protocols in the field, subdivided by reaction class as a 'toolbox' guide for organic synthesis.

Immobilization and Application of Fatty Acid Photodecarboxylase in Deep Eutectic Solvents

Since its discovery in 2017, the fatty acid decarboxylase (FAP) photoenzyme has been the focus of extensive research, given its ability to convert fatty acids into alka(e)nes using merely visible blue light. Unfortunately, there are still some drawbacks that limit the applicability of this biocatalyst, such as poor solubility of the substrates in aqueous media, poor photostability, and the impossibility of reusing the catalyst for several cycles. In this work, we demonstrate the use of FAP in non-conventional media as a free enzyme and an immobilized preparation. Namely, its applicability in deep eutectic solvents (DESs) and a proof-of-concept immobilization using a commercial His-tag selective carrier, a thorough study of reaction and immobilization conditions in each case, as well as reusability studies are shown. We observed an almost complete selectivity of the enzyme towards C18 decarboxylation over C16 when used in a DES, with a product analytical yield up to 81 % when using whole cells. Furthermore, when applying the immobilized enzyme in DES, we obtained yields >10-fold higher than the ones obtained in aqueous media.

Sustainable Production of Glycolipids by Biocatalyst on Renewable Deep Eutectic Solvents

Glycolipids have become an ecofriendly alternative to chemically obtained surfactants, mainly for the cosmetic, pharmaceutical, and food industries. However, the sustainable production of these compounds is still challenging, because: (i) water is a recognized inhibitor, (ii) multiphases make the use of cosolvent reaction medium necessary, and (iii) there are difficulties in finding a source for both starting materials. This study used sugars and lipids from peach palm fruit shells or model compounds as substrates to synthesize glycolipids on five different renewable deep eutectic solvents (Re-DES) alone or with a cosolvent system. Substrate conversions up to 24.84% (so far, the highest reported for this reaction on DES), showing (1) the non-precipitation of glucose in the solvent, (2) emulsification and (3) low viscosity (e.g., more favorable mass transfer) as the main limiting factors for these heterogeneous enzymatic processes. The resulting conversion was reached using a cosolvent system Re-DES:DMSO:t-butanol that was robust enough to allow conversions in the range 19–25%, using either model compounds or sugar and fatty acid extracts, with free or immobilized enzymes. Finally, the characterization of the in-house synthesized glycolipids by surface tension demonstrated their potential as biosurfactants, for instance, as an alternative to alcohol ethoxylates, industrially produced using less sustainable methods.