Microbial Biodegradation of Plastics: Methods for Assessing Degradation Mechanisms and Optimization Strategies

With the rapid growth of plastic production, plastic pollution has become increasingly widespread and persistent in the environment. This persistent pollution poses potential risks to ecosystems and human health. Microbial biodegradation offers a promising approach to plastic waste management because it operates under mild reaction conditions and has potential for sustainable application. This review summarizes recent advances in the major microbial groups involved in plastic biodegradation, methods for assessing degradation efficiency, underlying mechanisms, and strategies for improving degradation performance. Assessment methods are discussed, from physicochemical characterization to biochemical validation. Meanwhile, it emphasizes that real plastic biodegradation and degradation efficiency require multiple complementary lines of evidence to judge in a more complete and objective way. The complete process and molecular mechanisms of microbial plastic degradation are then described, including microbial attachment and biofilm formation, enzymatic degradation, intracellular metabolism, and mineralization of degradation products. In addition, it summarizes various efficiency optimization strategies for degradation, including plastic pretreatment, bioaugmentation, and regulation of environmental parameters. The lack of standardized assessment, limited practical translation, and ecological risks are the identified key challenges. Finally, standardized efficiency evaluation strategies, plastic upcycling, and emerging technologies for subsequent development were discussed. This review aims to provide a reference for understanding microbial plastic degradation.