聚氯乙烯（PVC）废弃物的积累已造成严重的环境污染，生物降解是解决该问题的有效途径之一，备受关注。然而，PVC的生物降解在降解酶和基因的研究方面进展缓慢，制约了PVC生物降解机制的研究进程。申请人前期获得了草地贪夜蛾肠道内生菌Klebsiella variicola分泌的PVC降解酶-醛脱氢酶，本项目拟通过高通量活性测定技术优化醛脱氢酶降解PVC的条件；在此基础上利用气相色谱-质谱、超高效液相色谱-串联质谱、核磁共振和元素分析等手段检测醛脱氢酶降解PVC的产物，解析PVC的降解途径；利用冷冻电镜技术和计算机分子模拟技术解析并确定醛脱氢酶与PVC相互作用的关键氨基酸位点，辅以氨基酸定点突变技术对关键氨基酸位点进行验证，最终明确醛脱氢酶降解PVC的作用机制。本项目的实施将增加PVC生物降解相关的降解酶资源，丰富PVC生物降解的基础理论，为环境中尤其是农业生产中PVC薄膜废弃物的处理提供新思路。

The accumulation of polyvinyl chloride (PVC) waste has caused serious environmental pollution. Biodegradation is one of the effective ways to solve this problem and has attracted much attention. However, research progress on the biodegradation of PVC is slow, and degradation enzymes and genes are rarely reported, which restricts the research process of PVC biodegradation mechanism. The applicant obtained the aldehyde dehydrogenase which can degrade PVC secreted by the intestinal endophytic bacterium Klebsiella variicola of Spodoptera frugiperda in the early stage. This project intends to optimize the conditions for aldehyde dehydrogenase to degrade PVC through high-throughput activity determination technology. Next, gas chromatography-mass spectrometry, ultra performance liquid chromatography-tandem mass spectrometry, nuclear magnetic resonance and elemental analysis will be used to detect the degradation products of aldehyde dehydrogenase on PVC, then analyze the potential degradation pathways of PVC. And then the key amino acid sites of the interaction between aldehyde dehydrogenase and PVC are analyzed and determined by cryo-electron microscopy and computer molecular simulation technology, supplemented by amino acid site-directed mutagenesis technology to verify the key amino acid sites. Finally the degradation mechanism of aldehyde dehydrogenase degrading PVC could be clarified. The implementation of this project will increase the resources of degradation enzymes related to PVC biodegradation, enrich the basic theories of PVC biodegradation, and provide new ideas for the treatment of PVC film waste in the environment, especially in agricultural production.