Rebecca A Wilkes, Nanqing Zhou, Austin L Carroll, Ojaswi Aryal, Kelly P Teitel, Rebecca S Wilson, Lichun Zhang, Arushi Kapoor, Edgar Castaneda, Adam M Guss, Jacob R Waldbauer, Ludmilla Aristilde
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引用次数: 0
Abstract
Comamonadaceae bacteria are enriched on poly(ethylene terephthalate) (PET) microplastics in wastewaters and urban rivers, but the PET-degrading mechanisms remain unclear. Here, we investigated these mechanisms with Comamonas testosteroniKF-1, a wastewater isolate, by combining microscopy, spectroscopy, proteomics, protein modeling, and genetic engineering. Compared to minor dents on PET films, scanning electron microscopy revealed significant fragmentation of PET pellets, resulting in a 3.5-fold increase in the abundance of small nanoparticles (<100 nm) during 30-day cultivation. Infrared spectroscopy captured primarily hydrolytic cleavage in the fragmented pellet particles. Solution analysis further demonstrated double hydrolysis of a PET oligomer, bis(2-hydroxyethyl) terephthalate, to the bioavailable monomer terephthalate. Supplementation with acetate, a common wastewater co-substrate, promoted cell growth and PET fragmentation. Of the multiple hydrolases encoded in the genome, intracellular proteomics detected only one, which was found in both acetate-only and PET-only conditions. Homology modeling of this hydrolase structure illustrated substrate binding analogous to reported PET hydrolases, despite dissimilar sequences. Mutants lacking this hydrolase gene were incapable of PET oligomer hydrolysis and had a 21% decrease in PET fragmentation; re-insertion of the gene restored both functions. Thus, we have identified constitutive production of a key PET-degrading hydrolase in wastewater Comamonas, which could be exploited for plastic bioconversion.
Comamonadaceae 细菌在废水和城市河流中的聚对苯二甲酸乙二酯(PET)微塑料上富集,但其降解 PET 的机制仍不清楚。在这里,我们通过结合显微镜、光谱学、蛋白质组学、蛋白质建模和基因工程等方法,对废水中分离出的 Comamonas testosteroniKF-1 进行了研究。与 PET 薄膜上的轻微凹痕相比,扫描电子显微镜发现 PET 颗粒明显破碎,导致小纳米颗粒(Comamonas,可用于塑料生物转化)的丰度增加了 3.5 倍。
期刊介绍:
Environmental Science & Technology (ES&T) is a co-sponsored academic and technical magazine by the Hubei Provincial Environmental Protection Bureau and the Hubei Provincial Academy of Environmental Sciences.
Environmental Science & Technology (ES&T) holds the status of Chinese core journals, scientific papers source journals of China, Chinese Science Citation Database source journals, and Chinese Academic Journal Comprehensive Evaluation Database source journals. This publication focuses on the academic field of environmental protection, featuring articles related to environmental protection and technical advancements.