School of Biotechnology and Key Laboratory of Industrial Biotechnology Ministry of Education, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China; International Joint Laboratory on Food Safety, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China.
School of Biotechnology and Key Laboratory of Industrial Biotechnology Ministry of Education, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China; International Joint Laboratory on Food Safety, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China.
J Environ Manage. 2024 Jun;361:121258. doi: 10.1016/j.jenvman.2024.121258. Epub 2024 May 29.
The rising accumulation of poly(ethylene terephthalate) (PET) waste presents an urgent ecological challenge, necessitating an efficient and economical treatment technology. Here, we developed chemical-biological module clusters that perform chemical pretreatment, enzymatic degradation, and microbial assimilation for the large-scale treatment of PET waste. This module cluster included (i) a chemical pretreatment that involves incorporating polycaprolactone (PCL) at a weight ratio of 2% (PET:PCL = 98:2) into PET via mechanical blending, which effectively reduces the crystallinity and enhances degradation; (ii) enzymatic degradation using Thermobifida fusca cutinase variant (4Mz), that achieves complete degradation of pretreated PET at 300 g/L PET, with an enzymatic loading of 1 mg protein per gram of PET; and (iii) microbial assimilation, where Rhodococcus jostii RHA1 metabolizes the degradation products, assimilating each monomer at a rate above 90%. A comparative life cycle assessment demonstrated that the carbon emissions from our module clusters (0.25 kg CO-eq/kg PET) are lower than those from other established approaches. This study pioneers a closed-loop system that seamlessly incorporates pretreatment, degradation, and assimilation processes, thus mitigating the environmental impacts of PET waste and propelling the development of a circular PET economy.
聚对苯二甲酸乙二醇酯 (PET) 废物的积累日益增多，给生态环境带来了严峻挑战，因此需要开发高效、经济的处理技术。本研究开发了一种化学-生物模块集群，用于大规模处理 PET 废物，包括化学预处理、酶降解和微生物同化。该模块集群包括：(i) 采用机械共混的方法，将重量比为 2%的聚己内酯（PCL）掺入 PET 中，可有效降低结晶度并提高降解效率；(ii) 使用耐热脂肪酶变体（4Mz）进行酶降解，在 300 g/L PET 下酶用量为每克 PET 1 毫克蛋白时，可实现预处理 PET 的完全降解；(iii) 微生物同化，罗德里格斯氏菌（Rhodococcus jostii RHA1）代谢降解产物，每个单体的同化率均高于 90%。生命周期评估表明，与其他已建立的方法相比，我们的模块集群的碳排放量（0.25 kg CO-eq/kg PET）更低。该研究开创了一种闭环系统，无缝集成了预处理、降解和同化过程，从而减轻了 PET 废物对环境的影响，推动了循环 PET 经济的发展。
