Enzymatic Polymerization as a Green Approach to Synthesizing Bio-Based Polyesters

Abstract

Given the fossil fuel crisis and the steady consumption of finite resources, the use of green polymers is becoming necessary. However, the term “green” describes materials that present green properties (such as biological origin and/or biodegradability) and are produced via sustainable processes conducted under mild conditions and not requiring the use of chemical catalysts, toxic solvents or reagents. Truly green materials must combine these characteristics; consequently, enzymatically synthesized bio-based and/or biodegradable polymers can be characterized as truly green. The present review focuses on the most promising, commercially available aliphatic and alipharomatic polyesters that can be synthesized enzymatically. In particular, the recent developments in the enzymatic polymerization of PLA and PBS and alipharomatic furan-based polyesters (e.g., PBF) are herein analyzed. Based on this analysis, it can be concluded that important steps have been taken toward synthesizing sustainably green polymers. Still, it is necessary to evaluate the applied methods regarding their capability to be used on an industrial scale.

Greener Synthesis Route for Furanic-Aliphatic Polyester: Enzymatic Polymerization in Ionic Liquids and Deep Eutectic Solvents

“…Enzymatic polymerization is renowned as a powerful method in sustainable polymer synthesis due to its selectivity, high efficiency, and sustainability. ,,− Enzymatic synthesis of different polymers, including FDCA-based polyesters, has been reported in recent years. ,− To achieve a high molecular weight polymer product, the optimization of enzyme-catalyzed polymerization was extensively studied, i.e., using different procedures (one-step and two-step polymerization) and varying reaction temperature or pressure. , In addition, the effects of polymerization conditions, including oligomerization time, vacuum, catalyst dosage, the usage of several comonomers, and reaction medium, have been reported as well. ,,,, Despite this vast progress in enzymatic polymerization, there is still room for improvement, for example, the replacement of organic solvents that are considered harmful to the environment.…”

Antimicrobial Activity of Composites-Based on Biopolymers

“…Biopolymers are materials obtained from renewable resources [58,59]. Despite the exciting properties of biopolymers, such as biocompatibility and environmental sustainability, they do not present antimicrobial properties (except chitosan).…”

“…The action route is usually through quaternary ammonium groups, which can interact hydrophobically with the bacterial cell wall to provoke cell death [76]. A polymeric matrix has a cationic nature due to the positive charge density, which can reduce the transmission of external nutrients necessary for cell viability [59], or the matrix can diffuse into the nucleus to inhibit their synthesis [79].…”

Recent Advances in the Enzymatic Synthesis of Polyester

“…Therefore, the degree of branching of PGS can be controlled by adjusting the substrate ratio to meet the needs of medical applications. Enzymatic polycondensation offers a greener way to synthesize polyesters from many bio-based monomers, which could reduce environmental and health impacts, and therefore, enzymatic polycondensation has received considerable attention in recent years [ 3 , 4 , 39 , 54 ].…”

“…Traditional saturated polyesters, which include polybutylene terephthalate (PBT) and polyethylene terephthalate (PET) that have high mechanical strength, abrasion resistance, corrosion resistance, and temperature resistance, as well as other outstanding properties, have been widely used as synthetic fibers and engineering plastics. With the “white pollution” intensified, polylactic acid (PLA), polybutylene succinate (PBS), and other bioplastics have been designed and manufactured [ 3 , 4 ]. These bioplastics have good biodegradability, biocompatibility, and non-toxicity characteristic, and they can be an alternative material to replace traditional plastics in medical and healthcare industry [ 5 , 6 ].…”