Bio-based and Biodegradable Glutarate Polyesters from Lignocellulosic Biomass

Apisata Holt^1,2, Yajan Yan^1,2,3, and Jason Locklin^1,2,3

¹Department of Chemistry, University of Georgia, Athens, Georgia, 30602, United States,

²New Materials Institute, University of Georgia, Athens, Georgia, 30602, United States,

³College of Engineering, University of Georgia, Athens, Georgia, 30602, United States

Recently, the development of bio-based polymers has attracted considerable attention, due to its compostable and biocompatible nature. Succinic acid (C4) has largely been explored and demonstrated commercial viability as a bio-based monomer.¹ Surprisingly, there has been less exploration for using glutaric acid (C5) in polymeric structures, and there currently are no reports of using it as a bio-based monomer. As a renewable resource from agricultural residue, lignocellulosic biomass can be converted to sugar which is transformed into glutaric acid by microbial biosynthesis.^2,3 This study explored the potential of using glutaric acid (C5) as monomer in melt polycondensation to synthesize glutarate bio-based polyesters. We synthesized a variety of glutarate bio-based polyesters by varying the ratio of the glutaric acid with a range of different diols, and additionally with alternate combinations of co-monomers. Glutarate bio-based polyesters were polymerized in a rotary evaporator at 165°C under controlled vacuum conditions. We found that the synthesized glutarate bio-based polyesters, when blended with other polymers, created beneficial additives. The properties of the blends between bio-based plastics and glutarate bio-based polyesters were examined by means of differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), tensile testing, atomic force microscopy (AFM), scanning electron microscope (SEM), and respirometer. The results suggested that glutarate bio-based polyesters improved the properties of blended polymers and offer an environmentally friendly alternative to petroleum-based additives.

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2. Wang, J.; Wu, Y.; Sun, X.; Yuan, Q.; Yan, Y., De Novo Biosynthesis of Glutarate via α-Keto Acid Carbon Chain Extension and Decarboxylation Pathway in Escherichia coli. ACS Synthetic Biology. 2017, 6 (10), 1922-1930.

3. Wang, J.; Shen, X.; Lin, Y.; Chen, Z.; Yang, Y.; Yuan, Q.; Yan, Y., Investigation of the Synergetic Effect of Xylose Metabolic Pathways on the Production of Glutaric Acid. ACS Synthetic Biology. 2018, 7 (1), 24-29.