J. Appl. Cryst.の発刊に際して

http://pubs.acs.org/doi/pdfplus/10.1021/cr300162p

Deep Eutectic Solvents (DESs) and Their Applications

Within the framework of green chemistry, solvents occupy a strategic place. To be qualified as a green medium, these solvents have to meet different criteria such as availability, non-toxicity, biodegradability, recyclability, flammability, and low price among others. Up to now, the number of available green solvents are rather limited. Here we wish to discuss a new family of ionic fluids, so-called Deep Eutectic Solvents (DES), that are now rapidly emerging in the current literature. A DES is a fluid generally composed of two or three cheap and safe components that are capable of self-association, often through hydrogen bond interactions, to form a eutectic mixture with a melting point lower than that of each individual component. DESs are generally liquid at temperatures lower than 100 °C. These DESs exhibit similar physico-chemical properties to the traditionally used ionic liquids, while being much cheaper and environmentally friendlier. Owing to these remarkable advantages, DESs are now of growing interest in many fields of research. In this review, we report the major contributions of DESs in catalysis, organic synthesis, dissolution and extraction processes, electrochemistry and material chemistry. All works discussed in this review aim at demonstrating that DESs not only allow the design of eco-efficient processes but also open a straightforward access to new chemicals and materials.

Deep eutectic solvents: syntheses, properties and applications

Over the past few decades, researchers have established artificial enzymes as highly stable and low-cost alternatives to natural enzymes in a wide range of applications. A variety of materials including cyclodextrins, metal complexes, porphyrins, polymers, dendrimers and biomolecules have been extensively explored to mimic the structures and functions of naturally occurring enzymes. Recently, some nanomaterials have been found to exhibit unexpected enzyme-like activities, and great advances have been made in this area due to the tremendous progress in nano-research and the unique characteristics of nanomaterials. To highlight the progress in the field of nanomaterial-based artificial enzymes (nanozymes), this review discusses various nanomaterials that have been explored to mimic different kinds of enzymes. We cover their kinetics, mechanisms and applications in numerous fields, from biosensing and immunoassays, to stem cell growth and pollutant removal. We also summarize several approaches to tune the activities of nanozymes. Finally, we make comparisons between nanozymes and other catalytic materials (other artificial enzymes, natural enzymes, organic catalysts and nanomaterial-based catalysts) and address the current challenges and future directions (302 references).

Nanomaterials with enzyme-like characteristics (nanozymes): next-generation artificial enzymes

基礎講座 電気泳動(Electrophoresis)

Over the past ten years, scientific and technological advances have established biocatalysis as a practical and environmentally friendly alternative to traditional metallo- and organocatalysis in chemical synthesis, both in the laboratory and on an industrial scale. Key advances in DNA sequencing and gene synthesis are at the base of tremendous progress in tailoring biocatalysts by protein engineering and design, and the ability to reorganize enzymes into new biosynthetic pathways. To highlight these achievements, here we discuss applications of protein-engineered biocatalysts ranging from commodity chemicals to advanced pharmaceutical intermediates that use enzyme catalysis as a key step.

Engineering the third wave of biocatalysis

A rule to predict which enantiomer of a secondary alcohol reacts faster in reactions catalyzed by cholesterol esterase, lipase from Pseudomonas cepacia, and lipase from Candida rugosa

Biocatalysis in ionic liquids – advantages beyond green technology

1 Introduction. 2 Designing Enantioselective Reactions. 2.1 Kinetic Resolutions. 2.2 Asymmetric Syntheses. 3 Choosing Reaction Media: Water and Organic Solvents. 3.1 Hydrolysis in Water. 3.2 Transesterifications and Condensations in Organic Solvents. 3.3 Other Reaction Media. 3.4 Immobilization. 4 Protein Sources and Optimization of Biocatalyst Performance. 4.1 Accessing Biodiversity. 4.2 Creating Improved Biocatalysts. 4.3 Catalytic Promiscuity in Hydrolases. 5 Lipases and Esterases. 5.1 Availability, Structures and Properties. 5.2 Survey of Enantioselective Lipase-Catalyzed Reactions. 5.3 Chemo-and Regioselective Lipase-Catalyzed Reactions. 5.4 Reactions Catalyzed by Esterases. 6 Proteases and Amidases. 6.1 Occurrence and Availability of Proteases and Amidases. 6.2 General Features of Subtilisin, Chymotrypsin, and Other Proteases and Amidases. 6.3 Structures of Proteases and Amidases. 6.4 Survey of Enantioselective Protease-and Amidase-Catalyzed Reactions. 7 Phospholipases. 7.1 Phospholipase A1. 7.2 Phospholipase A2. 7.3 Phospholipase C. 7.4 Phospholipase D. 8 Epoxide Hydrolases. 8.1 Introduction. 8.2 Mammalian Epoxide Hydrolases. 8.3 Microbial Epoxide Hydrolases. 9 Hydrolysis of Nitriles. 9.1 Introduction. 9.2 Mild Conditions. 9.3 Regioselective Reactions of Dinitriles. 9.4 Enantioselective Reactions. 10 Other Hydrolases. 10.1 Glycosidases. 10.2 Haloalcohol Dehalogenases. 10.3 Phosphotriesterases. Abbreviations. References. Index.

Hydrolases in Organic Synthesis: Regio- and Stereoselective Biotransformations

Polar organic solvents such as methanol or N-methylformamide inactivate lipases. Although ionic liquids such as 3-alkyl-1-methylimidazolium tetrafluoroborates have polarities similar to these polar organic solvents, they do not inactivate lipases. To get reliable lipase-catalyzed reactions in ionic liquids, we modified their preparation by adding a wash with aqueous sodium carbonate. Lipase-catalyzed reactions that previously did not occur in untreated ionic liquids now occur at rates comparable to those in nonpolar organic solvents such as toluene. Acetylation of 1-phenylethanol catalyzed by lipase from Pseudomonas cepacia (PCL) was as fast and as enantioselective in ionic liquids as in toluene. Ionic liquids permit reactions in a more polar solvent than previously possible. Acetylation of glucose catalyzed by lipase B from Candida antarctica (CAL-B) was more regioselective in ionic liquids because glucose is up to one hundred times more soluble in ionic liquids. Acetylation of insoluble glucose in organ...

Romas J. Kazlauskas

Papers

Engineering the third wave of biocatalysis

A rule to predict which enantiomer of a secondary alcohol reacts faster in reactions catalyzed by cholesterol esterase, lipase from Pseudomonas cepacia, and lipase from Candida rugosa

Biocatalysis in ionic liquids – advantages beyond green technology

Hydrolases in Organic Synthesis: Regio- and Stereoselective Biotransformations

Improved Preparation and Use of Room-Temperature Ionic Liquids in Lipase-Catalyzed Enantio- and Regioselective Acylations