Poly(ethylene terephthalate) (PET) is the most abundantly consumed synthetic polyester and accordingly a major source of plastic waste. The development of chemocatalytic approaches for PET depolymerization to monomers offers new options for open-loop upcycling of PET, which can leverage biological transformations to higher-value products. To that end, here we perform four sequential metabolic engineering efforts in Pseudomonas putida KT2440 to enable the conversion of PET glycolysis products via: (i) ethylene glycol utilization by constitutive expression of native genes, (ii) terephthalate (TPA) catabolism by expression of tphA2_IIA3_IIB_IIA1_II from Comamonas and tpaK from Rhodococcus jostii, (iii) bis(2-hydroxyethyl) terephthalate (BHET) hydrolysis to TPA by expression of PETase and MHETase from Ideonella sakaiensis, and (iv) BHET conversion to a performance-advantaged bioproduct, β-ketoadipic acid (βKA) by deletion of pcaIJ. Using this strain, we demonstrate production of 15.1 g/L βKA from BHET at 76% molar yield in bioreactors and conversion of catalytically depolymerized PET to βKA. Overall, this work highlights the potential of tandem catalytic deconstruction and biological conversion as a means to upcycle waste PET.

聚对苯二甲酸乙二醇酯 (PET) 是消耗量最大的合成聚酯，因此是塑料废物的主要来源。PET 解聚为单体的化学催化方法的发展为 PET 的开环升级循环提供了新的选择，可以利用生物转化为更高价值的产品。为此，我们在恶臭假单胞菌KT2440 中进行了四个连续的代谢工程工作，以通过以下方式实现 PET 糖酵解产物的转化：（i）通过天然基因的组成型表达利用乙二醇，（ii）通过表达的对苯二甲酸（TPA）分解代谢tphA2 _II A3 _II B _II A1 _II来自Comamonas和TPAK从红球菌jostii，（III），双（2-羟乙基）对苯二甲酸酯（BHET）水解为TPA通过表达PETase和MHETase从Ideonella sakaiensis，和（iv）BHET转换为性能优势的生物产物，β酮己二酸（βKA ) 通过删除pcaIJ。使用该菌株，我们证明了在生物反应器中以 76% 的摩尔产率从 BHET 生产 15.1 g/L βKA，并将催化解聚的 PET 转化为 βKA。总体而言，这项工作突出了串联催化解构和生物转化作为废 PET 升级回收手段的潜力。