Condition-dependent microbial and enzymatic degradation of PBAT, PLA, and PBS

Abstract The use of biodegradable plastics has increased steadily because of their biodegradability, biocompatibility, and processability. These materials are considered promising alternatives to conventional petroleum-derived plastics, which persist in the environment and cause serious pollution problems. Poly(butylene adipate-co-terephthalate) (PBAT), polylactic acid (PLA), and polybutylene succinate (PBS) are among the most widely used biodegradable polyesters. Their hydrolysable ester bonds make them susceptible to microbial and enzymatic attack. However, their degradation is often slow and incomplete under many environmental and experimental conditions, and degradation efficiency varies greatly depending on polymer structure, microbial strain, enzyme activity, temperature, medium composition, and exposure conditions. Recent studies therefore raise an important question: not simply whether these polyesters are biodegradable, but under which conditions their degradation becomes effective and how these condition-dependent processes can be connected to practical treatment and conversion routes. This review summarizes recent advances in the microbial and enzymatic degradation of PBAT, PLA, and PBS, with a focus on polymer features, common degradation mechanisms, degrading microorganisms and enzymatic hydrolysis, condition-dependent degradation, and remaining challenges for practical biodegradation. Future research should connect enzyme engineering for depolymerization with microbial metabolism of polymer-derived products, providing a more realistic framework for converting PBAT, PLA, and PBS into value-added compounds.