Comparative Performance of PETase as a Function of Reaction Conditions, Substrate Properties, and Product Accumulation
Comparative Performance of PETase as a Function of Reaction Conditions, Substrate Properties, and Product Accumulation
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PETase 的性能比较随反应条件、底物性质和产物积累的变化
DOI：
10.1002/cssc.202102517
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发表时间：
2021
期刊：
影响因子：
8.4
通讯作者：
Erickson E
中科院分区：
文献类型：
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作者：
Erickson E
人们对开发回收塑料聚对苯二甲酸乙二醇酯（PET）的新技术非常感兴趣。为此，PET水解酶的使用已显示出PET解构为其单体对苯二甲酸酯（TPA）和乙二醇（EG）的前景。在这里，Ideonella sakaiensisPETase野生型酶与先前报道的改进变体（W159 H/S238 F）进行了比较。比较了每种酶的热稳定性，并描述了突变体的1.45 nm分辨率结构，突出显示了与野生型酶相比底物结合裂缝的变化。 随后，将野生型和变体酶的性能作为温度、底物形态和反应混合物组成的函数进行比较。这些研究表明，反应温度对两种酶的性能影响最大。还表明，相对于无定形底物，两种酶对于具有中等结晶度的底物实现了更高水平的PET转化。最后，针对PET和对苯二甲酸双（2-羟乙基）酯（BHET）的水解，评估了产物积累对反应进程的影响。每种酶对对苯二甲酸单（2-羟乙基）酯（MHET）和TPA显示出不同的抑制曲线，而两者对EG的抑制敏感。总的来说，这项研究强调了反应条件，底物选择和产物积累对PET水解酶催化性能的重要性，这对酶基聚酯回收开发中的酶筛选具有影响。
There is keen interest to develop new technologies to recycle the plastic poly(ethylene terephthalate) (PET). To this end, the use of PET‐hydrolyzing enzymes has shown promise for PET deconstruction to its monomers, terephthalate (TPA) and ethylene glycol (EG). Here, theIdeonella sakaiensisPETase wild‐type enzyme was compared to a previously reported improved variant (W159H/S238F). The thermostability of each enzyme was compared and a 1.45 Å resolution structure of the mutant was described, highlighting changes in the substrate binding cleft compared to the wild‐type enzyme. Subsequently, the performance of the wild‐type and variant enzyme was compared as a function of temperature, substrate morphology, and reaction mixture composition. These studies showed that reaction temperature had the strongest influence on performance between the two enzymes. It was also shown that both enzymes achieved higher levels of PET conversion for substrates with moderate crystallinity relative to amorphous substrates. Finally, the impact of product accumulation on reaction progress was assessed for the hydrolysis of both PET and bis(2‐hydroxyethyl) terephthalate (BHET). Each enzyme displayed different inhibition profiles to mono(2‐hydroxyethyl) terephthalate (MHET) and TPA, while both were sensitive to inhibition by EG. Overall, this study highlights the importance of reaction conditions, substrate selection, and product accumulation for catalytic performance of PET‐hydrolyzing enzymes, which have implications for enzyme screening in the development of enzyme‐based polyester recycling.