One-Pot Chemo-bioprocess of PET Depolymerization and Recycling Enabled by a Biocompatible Catalyst, Betaine
One-Pot Chemo-bioprocess of PET Depolymerization and Recycling Enabled by a Biocompatible Catalyst, Betaine
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DOI：
10.1021/acscatal.0c04014
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发表时间：
2021-03-23
期刊：
影响因子：
12.9
通讯作者：
Kim, Kyoung Heon
中科院分区：
文献类型：
--
作者：
Kim, Dong Hyun;Han, Dong Oh;Kim, Kyoung Heon
聚对苯二甲酸乙酯（PET）由于其独特的物理性能而广泛应用于各个行业。然而，由于PET的可降解性和回收率低，在全球范围内引起了重大的环境问题。由于几乎不可能用其他材料替代PET，因此有效的PET回收方法对于循环经济是必要的。在此，为了向PET组分资源回收方法的范式转变，我们开发了一种集成的PET解聚工艺，并在一锅工艺中将PET单体转化为高价值产品。我们方法的关键是在糖酵解过程中使用生物相容性催化剂甜菜碱，使整个PET糖酵解浆作为底物直接应用于进一步的生物过程。基于密度泛函数理论（DFT）分析，甜菜碱通过甜菜碱、EG和PET之间的两个强氢相互作用以及甜菜碱阴离子和阳离子基之间的协同作用，有效地催化了PET的解聚。通过甜菜碱对PET进行糖酵解，优化PET糖酵解浆的酶解工艺，以高滴度、高产率将PET解聚为对苯二甲酸酯（TPA, 31.0 g/L, 62.8%, mol/mol）和乙二醇（EG, 11.7 g/L, 63.3%, mol/mol）。该工艺进一步应用于PET水解产物中TPA和EG的生物转化，分别为原儿茶酸（PCA）和乙醇酸（GLA）。这种集化学糖酵解、酶解、生物转化为一体的一锅式化学生物工艺对PET解聚和回收具有很高的应用价值。
Poly(ethylene terephthalate) (PET) has been widely used in various industries due to its unique physical properties. However, PET causes major environmental problems globally due to its low degradability and recycling rate. Since it is nearly impossible to replace PET with other materials, an efficient approach for PET recycling is necessary for a circular economy. Herein, for a paradigm shift toward the approach for resource recovery of PET components, we developed an integrated process for depolymerizing PET and converting PET monomers to high-value products in a one-pot process. The key of our approach is the use of the biocompatible catalyst betaine in a glycolysis process that enables whole PET glycolysis slurry as a substrate to be directly applied to further bioprocesses. Based on the density functional theory (DFT) analysis, betaine effectively catalyzed PET depolymerization by two strong hydrogen interactions between betaine, EG, and PET as well as by the synergetic effect between the anion and cation groups of betaine. Through the glycolysis of PET with betaine and the optimized enzymatic hydrolytic process for the PET glycolysis slurry, PET was depolymerized to terephthalate (TPA, 31.0 g/L, 62.8%, mol/mol) and ethylene glycol (EG, 11.7 g/L, 63.3%, mol/mol) at high titers and high yields. This process was further applied to the bioconversion of TPA and EG present in the PET hydrolysate to protocatechuic acid (PCA) and glycolic acid (GLA), respectively. This one-pot chemo-bioprocess integrating chemical glycolysis, enzymatic hydrolysis, and bioconversion for PET depolymerization and recycling was suggested to be highly applicable to the upcycling of waste PET.