Ma Hairong, Khusnutdinova Anna N, Lemak Sofia, Chernikova Tatyana N, Golyshina Olga V, Almendral David, Ferrer Manuel, Golyshin Peter N, Yakunin Alexander F
Centre for Environmental Biotechnology, School of Environmental and Natural Sciences, Bangor University, Bangor, UK.
Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Canada.
J Hazard Mater. 2025 Jan 5;481:136540. doi: 10.1016/j.jhazmat.2024.136540. Epub 2024 Nov 16.
Enzyme-based depolymerization of plastics, including polyesters, has emerged as a promising approach for plastic waste recycling and reducing environmental plastic pollution. Currently, most of the known polyester-degrading enzymes are represented by a few natural and engineered PETases from the carboxylesterase family V. To identify novel groups of polyesterases, we selected 25 proteins from the carboxylesterase family IV, which share 22 % to 80 % sequence identity to the metagenomic thermophilic polyesterase IS12. All purified proteins were found to be active against chromogenic para-nitrophenyl esters with a preference for short acyl chains. Screening for polyesterase activity using emulsified polyesters demonstrated the presence of hydrolytic activity against bis(benzoyloxyethyl) terephthalate (3PET), polycaprolactone (PCL), and polylactic acid (PLA) in all tested proteins. Biochemical characterization of four selected polyesterases revealed high thermostability in CBA10055, whereas the mesophilic GEN0105 exhibited higher polyesterase activity. Two ancestral variants of GEN0105 showed higher thermostability and activity against PCL and PLA, but reduced activity with amorphous PET. Furthermore, six established PETases were found to be highly active against PCL and PLA. Thus, our results indicate that polyesterase activity is widespread in the family IV carboxylesterases, and that most polyesterases are promiscuous being able to degrade different polyesters.
基于酶的塑料解聚，包括聚酯，已成为塑料废物回收和减少环境塑料污染的一种有前景的方法。目前，大多数已知的聚酯降解酶由来自羧酸酯酶家族V的一些天然和工程化的PET酶代表。为了鉴定新型聚酯酶组，我们从羧酸酯酶家族IV中选择了25种蛋白质，它们与宏基因组嗜热聚酯酶IS12的序列同一性为22%至80%。所有纯化的蛋白质都被发现对生色对硝基苯酯有活性，且偏好短酰基链。使用乳化聚酯筛选聚酯酶活性表明，所有测试蛋白质中都存在针对双（苯甲酰氧基乙基）对苯二甲酸酯（3PET）、聚己内酯（PCL）和聚乳酸（PLA）的水解活性。对四种选定聚酯酶的生化表征显示，CBA100-55具有高热稳定性，而嗜温的GEN0105表现出更高的聚酯酶活性。GEN0105的两个祖先变体对PCL和PLA表现出更高的热稳定性和活性，但对无定形PET的活性降低。此外，发现六种已确定的PET酶对PCL和PLA具有高活性。因此，我们的结果表明聚酯酶活性在羧酸酯酶家族IV中广泛存在，并且大多数聚酯酶具有多底物特异性，能够降解不同的聚酯。
