Plant biomass is an abundant renewable resource on Earth. Microorganisms harvest energy from plant material by means of complex enzymatic systems that efficiently degrade natural polymers. Intriguingly, microorganisms have evolved to exploit these ancient mechanisms to also decompose synthetic plastic polymers. In this Review, we summarize the mechanisms by which they decompose non-starch plant biomass and the six major types of synthetic plastics. We focus on the structural features of the enzymes that contribute to substrate recognition and then describe the catalytic mechanisms of polymer metabolism. An understanding of these natural biocatalysts is valuable if we are to exploit their potential for the degradation of synthetic polymers.

植物生物质是地球上丰富的可再生资源。微生物通过复杂的酶系统有效地降解天然聚合物，从植物材料中获取能量。有趣的是，微生物已经进化到利用这些古老的机制来分解合成塑料聚合物。在这篇综述中，我们总结了它们分解非淀粉植物生物质和六种主要合成塑料的机制。我们关注有助于底物识别的酶的结构特征，然后描述聚合物代谢的催化机制。如果我们要利用它们降解合成聚合物的潜力，了解这些天然生物催化剂是很有价值的。