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Conversion of plastic wastes to fatty acids is an attractive means to supplement the sourcing of these high-value, high-volume chemicals. We report a method for transforming polyethylene (PE) and polypropylene (PP) at ~80% conversion to fatty acids with number-average molar masses of up to ~700 and 670 daltons, respectively. The process is applicable to municipal PE and PP wastes and their mixtures. Temperature-gradient thermolysis is the key to controllably degrading PE and PP into waxes and inhibiting the production of small molecules. The waxes are upcycled to fatty acids by oxidation over manganese stearate and subsequent processing. PP ꞵ-scission produces more olefin wax and yields higher acid-number fatty acids than does PE ꞵ-scission. We further convert the fatty acids to high-value, large–market-volume surfactants. Industrial-scale technoeconomic analysis suggests economic viability without the need for subsidies.
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Herbarium specimens as tools for exploring the evolution of fatty acid‐derived natural products in plants
SUMMARY Plants synthesize natural products via lineage‐specific offshoots of their core metabolic pathways, including fatty acid synthesis. Recent studies have shed light on new fatty acid‐derived natural products and their biosynthetic pathways in disparate plant species. Inspired by this progress, we set out to develop tools for exploring the evolution of fatty‐acid derived products. We sampled multiple species from all major clades of euphyllophytes, including ferns, gymnosperms, and angiosperms (monocots and eudicots), and we show that the compositional profiles (though not necessarily the total amounts) of fatty‐acid derived surface waxes from preserved plant specimens are consistent with those obtained from freshly collected tissue in a semi‐quantitative and sometimes quantitative manner. We then sampled herbarium specimens representing 57 monocot species to assess the phylogenetic distribution and evolution, of two fatty acid‐derived natural products found in that clade: beta‐diketones and alkylresorcinols. These chemical data, combined with analyses of 26 monocot genomes, revealed a co‐occurrence (though not necessarily a causal relationship) between whole genome duplication and the evolution of diketone synthases from an ancestral alkylresorcinol synthase‐like polyketide synthase. Limitations of using herbarium specimen wax profiles as proxies for those of fresh tissue seem likely to include effects from loss of epicuticular wax crystals, effects from preservation techniques, and variation in wax chemical profiles due to genotype or environment. Nevertheless, this work reinforces the widespread utility of herbarium specimens for studying leaf surface waxes (and possibly other chemical classes) and reveals some of the evolutionary history of fatty acid‐derived natural products within monocots.
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- Award ID(s):
- 2232106
- PAR ID:
- 10535180
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- The Plant Journal
- Volume:
- 120
- Issue:
- 1
- ISSN:
- 0960-7412
- Format(s):
- Medium: X Size: p. 9-18
- Size(s):
- p. 9-18
- Sponsoring Org:
- National Science Foundation
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