Institute for Environmental Genomics, Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma 73019, United States.
Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843, United States.
Environ Sci Technol. 2023 Sep 19;57(37):13901-13911. doi: 10.1021/acs.est.3c03778. Epub 2023 Sep 8.
Polyethylene (PE) is the most widely produced synthetic polymer and the most abundant plastic waste worldwide due to its recalcitrance to biodegradation and low recycle rate. Microbial degradation of PE has been reported, but the underlying mechanisms are poorly understood. Here, we isolated a strain A34 from 609 day enriched cultures derived from naturally weathered plastic waste and identified the potential key PE degradation enzymes. After 30 days incubation with A34, 1% weight loss was achieved. Decreased PE molecular weight, appearance of C-O and C═O on PE, palmitic acid in the culture supernatant, and pits on the PE surface were observed. Proteomics analysis identified multiple key PE oxidation and depolymerization enzymes including one multicopper oxidase, one lipase, six esterase, and a few lipid transporters. Network analysis of proteomics data demonstrated the close relationships between PE degradation and metabolisms of phenylacetate, amino acids, secondary metabolites, and tricarboxylic acid cycles. The metabolic roadmap generated here provides critical insights for optimization of plastic degradation condition and assembly of artificial microbial communities for efficient plastic degradation.
聚乙烯（PE）是世界上产量最大的合成聚合物，也是最丰富的塑料废物，因为它难以生物降解且回收利用率低。已经有报道称微生物可以降解 PE，但其中的潜在机制仍知之甚少。在这里，我们从自然风化的塑料废物中富集培养 609 天后分离出一株 A34 菌株，并鉴定出了潜在的关键 PE 降解酶。经过 30 天的 A34 培养，PE 的重量损失达到了 1%。PE 的分子量降低，PE 表面出现 C-O 和 C═O，培养上清液中出现棕榈酸，PE 表面出现凹坑。蛋白质组学分析鉴定出多种关键的 PE 氧化和解聚酶，包括一种多铜氧化酶、一种脂肪酶、六种酯酶和一些脂质转运蛋白。蛋白质组学数据的网络分析表明，PE 降解与苯乙酸、氨基酸、次生代谢物和三羧酸循环的代谢密切相关。这里生成的代谢途径图为优化塑料降解条件和组装高效塑料降解的人工微生物群落提供了重要的见解。
