The present article comprehensively reviews the macromolecular synthesis using enzymes as catalysts. Among the six main classes of enzymes, the three classes, oxidoreductases, transferases, and hydrolases, have been employed as catalysts for the in vitro macromolecular synthesis and modification reactions. Appropriate design of reaction including monomer and enzyme catalyst produces macromolecules with precisely controlled structure, similarly as in vivo enzymatic reactions. The reaction controls the product structure with respect to substrate selectivity, chemo-selectivity, regio-selectivity, stereoselectivity, and choro-selectivity. Oxidoreductases catalyze various oxidation polymerizations of aromatic compounds as well as vinyl polymerizations. Transferases are effective catalysts for producing polysaccharide having a variety of structure and polyesters. Hydrolases catalyzing the bond-cleaving of macromolecules in vivo, catalyze the reverse reaction for bond forming in vitro to give various polysacchar...

Enzymes as Green Catalysts for Precision Macromolecular Synthesis

Natural antioxidants as stabilizers for polymers

Background: Antibacterial films were prepared using sodium alginate (SA) and carboxymethyl cellulose (CMC) as a matrix, glycerin as a plasticizer and CaCl2 as a cross-linking agent, and by incorporating the natural antibacterial agent pyrogallic acid (PA). The present study describes the microstructure and the physical, barrier, mechanical, optical and antibacterial properties of blended films prepared by incorporating different concentrations of PA into the SA/CMC matrix.; Results: The microstructure of the films was investigated by Fourier transform infrared spectroscopy and scanning electron microscopy, which revealed that PA interacts with the SA/CMC matrix through hydrogen bonding. Moreover, the incorporation of PA increased the moisture content, water vapor permeability and oxygen permeability of SA/CMC films. Films containing 40 g kg-1 of PA had the highest elongation at break result (39.60%). Compared with pure SA/CMC films, the incorporation of PA improved the barrier properties against ultraviolet light; however, it decreased the color parameter L* value and increased the a* and b* values of the films. Furthermore, films with PA, especially at higher concentrations, were more effective against Escherichia coli and Staphylococcus aureus.; Conclusion: Antibacterial SA/CMC films incorporating PA appear to have good potential to enhance the safety of foods and food products. © 2016 Society of Chemical Industry.; © 2016 Society of Chemical Industry.

Sodium alginate/carboxymethyl cellulose films containing pyrogallic acid: physical and antibacterial properties.

Natural phenol polymers are widely represented in nature and include a variety of classes including tannins and lignins as the most prominent. Largely consumed foods are rich sources of phenol polymers, notably black foods traditionally used in East Asia, but other non-edible, easily accessible sources, e.g., seaweeds and wood, have been considered with increasing interest together with waste materials from agro-based industries, primarily grape pomace and other byproducts of fruit and coffee processing. Not in all cases were the main structural components of these materials identified because of their highly heterogeneous nature. The great beneficial effects of natural phenol-based polymers on human health and their potential in improving the quality of food were largely explored, and this review critically addresses the most interesting and innovative reports in the field of nutrition and biomedicine that have appeared in the last five years. Several in vivo human and animal trials supported the proposed use of these materials as food supplements and for amelioration of the health and production of livestock. Biocompatible and stable functional polymers prepared by peroxidase-catalyzed polymerization of natural phenols, as well as natural phenol polymers were exploited as conventional and green plastic additives in smart packaging and food-spoilage prevention applications. The potential of natural phenol polymers in regenerative biomedicine as additives of biomaterials to promote growth and differentiation of osteoblasts is also discussed.

https://www.mdpi.com/2076-3921/6/2/30/pdf

Natural Phenol Polymers: Recent Advances in Food and Health Applications.

Polyphenols, which by the Quideau definition are plant-derived chemicals with two or more phenolic groups, have attracted interest because of their antioxidant activity, adsorption on universal substrates, and biocompatibility. Most polyphenols include gallol groups in their chemical structures, which has inspired us to synthesize gallol-functionalized polymers. We report the reversible addition–fragmentation chain transfer polymerization of 3,4,5-trimethoxystyrene using cyanomethyl dodecyl trithiocarbonate as the chain transfer agent. This method produces well-defined polymers with a wide range of molecular weight (from 5.4 to 53.4 kg mol–1) and low polydispersity index (Mw/Mn < 1.3). Subsequent demethylation of poly(3,4,5-trimethoxystyrene) (PTMS) yields poly(3,4,5-trihydroxystyrene) (polyvinylgallol, PVGal). These newly synthesized polymers exhibit greater antioxidant activities than widely used catechol-functionalized polymers based on the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH), 2,2′-azinobis(3-...

Antioxidant and Adsorption Properties of Bioinspired Phenolic Polymers: A Comparative Study of Catechol and Gallol

Enzymatic synthesis of a polymeric antioxidant for efficient stabilization of polypropylene

Synthesis of ploy(p-methoxyphenol) and evaluation of its antioxidation behavior as an antioxidant in several ester oils

A novel antioxidant with high molecular weight was successfully synthesized via horseradish peroxide-catalyzed oxidative polymerization of pyrogallic acid. As-synthesized poly(pyrogallic acid), a black powder completely soluble in common organic solvents, has a number-averaged molecular weight of about several thousand and consists of phenylene and oxyphenylene units. Besides, as-prepared poly(pyrogallic acid) exhibits much better thermal stability and antioxidant capacity than butylated hydroxyanisole (denoted as BHA) and butylated hydroxytoluene (denoted as BHT), two kinds of commercial antioxidants. And it was also found that the higher phenolic content the pyrogallic acid polymer possess, the better antioxidant activity the poly(pyrogallic acid) shows. More importantly, poly(pyrogallic acid) could effectively inhibit the oxidation degradation of polypropylene (denoted as PP) during plastic processing. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41591.

Enzymatic oxidative polymerization of pyrogallic acid for preparation of hindered phenol antioxidant

The efficient polymerization of 4-methoxyphenol in an aqueous micelle system has been realized with horseradish peroxidase as an enzymatic catalyst and sodium dodecyl sulfate as a surfactant. The obtained polymer is a kind of light yellow powder, which is completely soluble in acetone, DMF, DMSO and THF. Particle size distribution and 1H NMR analysis indicate that the polymerization is performed mainly in the palisade layer of micelles. The number-average molecular weight of poly(4-methoxyphenol) measured by gel permeation chromatography (GPC) is about 1000. IR analysis shows that both phenylene and oxyphenylene units are contained in the polymer structure. Results of antioxidant activity tests indicate that poly(4-methoxyphenol) possesses excellent antioxidant properties and may be used as a highly efficient antioxidant agent.

Synthesis of poly(4-methoxyphenol) by enzyme-catalyzed polymerization and evaluation of its antioxidant activity

In this study, poly(4-aminophenol) was successfully prepared by an enzymatic reaction in water, with its molecular weights ranging from 12,000 to 52,000. The polymerization of 4-aminophenol produced high yields over a wide pH ranging from 4 to 10. In addition, poly(4-aminophenol) was also used for silver-ion adsorption because it was composed of amino and hydroxyl groups. We found that the adsorption capacity of poly(4-aminophenol) was relevant to the time, pH value, temperature, and concentration of silver ions, and the greatest adsorption capacity of poly(4-aminophenol) for silver ions was 220 mg/g. Moreover, a series of tests showed that the adsorption of silver ions was mainly achieved by a reduction reaction, and the silver nanoparticles were formed with a face-centered cubic structure, and their average particle size was about 10 nm. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40367.

Ke Zheng

Papers

Enzymatic synthesis of a polymeric antioxidant for efficient stabilization of polypropylene

Synthesis of ploy(p-methoxyphenol) and evaluation of its antioxidation behavior as an antioxidant in several ester oils

Enzymatic oxidative polymerization of pyrogallic acid for preparation of hindered phenol antioxidant

Synthesis of poly(4-methoxyphenol) by enzyme-catalyzed polymerization and evaluation of its antioxidant activity

Synthesis of poly(4-aminophenol) by horseradish peroxidase and the evaluation of its adsorptivity for silver ions