Pang Wenlong, Li Bin, Wu Yufeng, Tian Shaonan, Zhang Yu, Yang Jun
Institute of Circular Economy, Beijing University of Technology, Beijing, 100022, China; Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing, 100022, China; State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China.
Institute of Circular Economy, Beijing University of Technology, Beijing, 100022, China; Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing, 100022, China.
Int J Biol Macromol. 2023 Dec 31;253(Pt 7):127496. doi: 10.1016/j.ijbiomac.2023.127496. Epub 2023 Oct 17.
With global enforcement of plastic bans and restrictions, the biodegradable plastic, e.g., polylactic acid (PLA), has been extensively employed as a primary substitute for traditional petroleum-based plastics. However, the growing problem associated with PLA waste accumulation is posing grand environmental challenges. In addition, although PLA has the degrading property under natural conditions, the degradation process takes too long and the degradation products cannot be recycled. In this context, enzymatic degradation of PLA arouses great attention in scientific communities. This study aims at selecting the most cost-effective protease from various enzymes and optimizing the enzymolysis conditions towards the degradation of PLA. We will demonstrate that under an optimal temperature of 45 °C, a pH vale of 11, and an enzyme concentration of 0.6 mg mL, the protease K would achieve a remarkable degradation efficiency (> 99 %) for PLA films within just 50 min. Finally, molecular dynamics (MD) simulation and molecular docking studies reveal the mechanism behind the protease-induced PLA degradation, providing a promising direction for waste treatment and resource utilization for future biodegradable plastics.
随着全球对塑料禁令和限制的实施，可生物降解塑料，如聚乳酸（PLA），已被广泛用作传统石油基塑料的主要替代品。然而，与PLA废物积累相关的日益严重的问题正带来巨大的环境挑战。此外，尽管PLA在自然条件下具有降解特性，但降解过程耗时过长且降解产物无法回收利用。在此背景下，PLA的酶促降解在科学界引起了极大关注。本研究旨在从各种酶中筛选出最具成本效益的蛋白酶，并优化酶解条件以实现PLA的降解。我们将证明，在45℃的最佳温度、11的pH值和0.6mg/mL的酶浓度下，蛋白酶K在短短50分钟内就能对PLA薄膜实现显著的降解效率（>99%）。最后，分子动力学（MD）模拟和分子对接研究揭示了蛋白酶诱导PLA降解的背后机制，为未来可生物降解塑料的废物处理和资源利用提供了一个有前景的方向。
