Enzymatic Synthesis of Inulin-Containing Hydrogels

The Bacillus subtilis protease Proleather FG-F catalyzed the transesterification of inulin with vinyl acrylate (VA) in dimethylformamide (DMF). The reaction conversion for different VA concentrations was greater than 57% after 96 h at 50 °C. The degree of substitution (DS, defined as the amount of acrylate groups per 100 inulin fructofuranoside residues) with acrylate moieties can be controlled by varying the molar ratio of VA to inulin. Reasonable yields were obtained (44−51%, 2 days) using a two-step purification methodology. Inulin derivatized with VA (Inul-VA) was characterized by gel permeation chromatography, and its structure was established by 1H, 13C, and 1H−1H correlation spectroscopy and 1H−13C heteronuclear multiple quantum coherence NMR. The main positional isomer was at the 6 position of the fructofuranoside residue and two other minor isomers were observed at the 3 and 4 positions. Thus, the enzymatic reaction was largely regioselective. Furthermore, the inulin fructose residues were monosubstituted. Gels with swelling ratios at equilibrium of up to ca. 20 were prepared by free radical polymerization of aqueous solutions of Inul-VA with different DS and monomer concentrations. Gel pore sizes were calculated from swelling experiments and range from 19 to 57 Å. To our knowledge, this work reports the first successful enzymatic modification of a polysaccharide solubilized in 100% DMF solution

Enzymatic oligomerization and polymerization of arylamines: state of the art and perspectives

The literature concerning the oxidative oligomerization and polymerization of various arylamines, e.g., aniline, substituted anilines, aminonaphthalene and its derivatives, catalyzed by oxidoreductases, such as laccases and peroxidases, in aqueous, organic, and mixed aqueous organic monophasic or biphasic media, is reviewed. An overview of template-free as well as template-assisted enzymatic syntheses of oligomers and polymers of arylamines is given. Special attention is paid to mechanistic aspects of these biocatalytic processes. Because of the nontoxicity of oxidoreductases and their high catalytic efficiency, as well as high selectivity of enzymatic oligomerizations/polymerizations under mild conditions-using mainly water as a solvent and often resulting in minimal byproduct formation-enzymatic oligomerizations and polymerizations of arylamines are environmentally friendly and significantly contribute to a "green'' chemistry of conducting and redox-active oligomers and polymers. Current and potential future applications of enzymatic polymerization processes and enzymatically synthesized oligo/polyarylamines are discussed

Oxidative Reactions with Nonaqueous Enzymes

The objective of this work is to demonstrate a proof-of-concept of enzymatic oxidative processing in nonaqueous media using alkene epoxidation and phenolic polymerization as relevant targets. This project will provide both the fundamental and applied investigations necessary to initiate the implementation of oxidative biocatalysts as commercially relevant alternatives to chemical processing in general, and to phenolic polymerizations and alkene epoxidation specifically. Thus, this work will address the Bioprocessing Solicitation Area to: (1) makes major improvements to phenolic polymerization and alkene epoxidation technologies; (2) is expected to be cost competitive with competing conventional processes; and (3) produces higher yields with less waste

Biocatalytic Polytransesterification of Inulin with Divinyladipate

http://dx.doi.org/10.1021/cm020393

Network information services : The emergence of an industry

The authors discuss the characteristics and benefits of network information services (NIS), which are developing into an important new industry likely to have profound effects on society. Many of the services and possible applications are described. Three scenarios are analysed, in which the future of the industry may be directed by technology, the market, and policy issues. It is concluded that consumers and small businesses are unlikely to be able to achieve sufficient economies through NIS by the end of the century to make much use of the services provided. Large and medium companies, however, will be served by a diversified, multi-network marketplace. The issue of equality of access to information will become of significant public concern.