Search

Waste plastics represent major environmental and economic burdens due to their ubiquity, slow breakdown rates, and inadequacy of current recycling routes. Polyethylenes are particularly problematic, because they lack robust recycling approaches despite being the most abundant plastics in use today. We report a novel chemical and biological approach for the rapid conversion of polyethylenes into structurally complex and pharmacologically active compounds. We present conditions for aerobic, catalytic digestion of polyethylenes collected from post‐consumer and oceanic waste streams, creating carboxylic diacids that can then be used as a carbon source by the fungus Aspergillus nidulans. As a proof of principle, we have engineered strains of A. nidulans to synthesize the fungal secondary metabolites asperbenzaldehyde, citreoviridin, and mutilin when grown on these digestion products. This hybrid approach considerably expands the range of products to which polyethylenes can be upcycled. [ABSTRACT FROM AUTHOR]

Abstract: Cesium lead halide perovskites are an emerging class of quantum dots (QDs) that have shown promise in a variety of applications; however, their properties are highly dependent on their surface chemistry. To this point, the thermodynamics of ligand binding remain unstudied. Herein, 1H NMR methods were used to quantify the thermodynamics of ligand exchange on CsPbBr3 QDs. Both oleic acid and oleylamine native ligands dynamically interact with the CsPbBr3 QD surface, having individual surface densities of 1.2–1.7 nm−2. 10‐Undecenoic acid undergoes an exergonic exchange equilibrium with bound oleate (Keq=1.97) at 25 °C while 10‐undecenylphosphonic acid undergoes irreversible ligand exchange. Undec‐10‐en‐1‐amine exergonically exchanges with oleylamine (Keq=2.52) at 25 °C. Exchange occurs with carboxylic acids, phosphonic acids, and amines on CsPbBr3 QDs without etching of the nanocrystal surface; increases in the steady‐state PL intensities correlate with more strongly bound conjugate base ligands. [ABSTRACT FROM AUTHOR]

Keywords: Biosynthesis; Catalysis; Polyethylenes; Synthetic Biology; Upcycling EN Biosynthesis Catalysis Polyethylenes Synthetic Biology Upcycling 1 1 1 01/19/23 20230123 NES 230123 B A novel, two-step chemical-biological approach b converts post-consumer polyethylenes into structurally diverse and pharmacologically active fungal natural products, as reported by Travis J. Williams, Clay C. C. Wang et al. in their Research Article (e202214609). Polyethylenes are first cleaved into carboxylic diacids using catalytic oxidation. Polyethylenes are first cleaved into carboxylic diacids using catalytic oxidation. [Extracted from the article]