The drastically increasing amount of plastic waste is causing an environmental crisis that requires innovative technologies for recycling post-consumer plastics to achieve waste valorization while meeting environmental quality goals. Biocatalytic depolymerization mediated by enzymes has emerged as an efficient and sustainable alternative for plastic treatment and recycling. A variety of plastic-degrading enzymes have been discovered from microbial sources. Meanwhile, protein engineering has been exploited to modify and optimize plastic-degrading enzymes. This review highlights the recent trends and up-to-date advances in mining novel plastic-degrading enzymes through state-of-the-art omics-based techniques and improving the enzyme catalytic efficiency and stability via various protein engineering strategies. Future research prospects and challenges are also discussed. Biocatalytic depolymerization mediated by enzymes has emerged as an efficient and sustainable alternative for plastic treatment and recycling, which aims to reduce adverse environmental effects and recover valuable components from plastic waste.Metagenomic and proteomic approaches can be harnessed as powerful tools in mining enzymes capable of plastic depolymerization from a wide variety of environments and ecosystems.Plastic-degrading enzymes can be optimized by protein engineering for improved performance, including enhancement of enzyme thermostability, reinforcement of the binding of substrate to enzyme active site, enhancement of interaction between substrate and enzyme surface, and refinement of catalytic capacity.