(238f) Particle Size-Dependent Biodegradation Behavior and Morphological Changes of Biodegradable Microplastics

Microplastics originating from petroleum-based plastics persist in the environment due to their resistance to degradation, thereby posing significant and long-term environmental challenges. Biodegradable plastics have emerged as environmentally sustainable alternatives to petroleum-based plastics. However, the biodegradation behavior of microplastics derived from these materials remains inadequately understood and insufficiently characterized. A quantitative understanding of size-dependent degradation properties is essential for evaluating their environmental persistence and degradability.

In this study, biodegradable microplastics were classified into four size ranges (≤125 µm, 125–250 µm, 250–500 µm, and 500–1000 µm), and comparative biodegradation experiments were performed under controlled conditions simulating natural environments. The results revealed that smaller particles degraded significantly faster, highlighting a pronounced size-dependent effect. Scanning electron microscopy (SEM) was employed to observe size and surface changes of plastic particles in the 250–500 µm range, providing direct evidence of microbial degradation.

This study verifies the size-dependent biodegradation behavior of biodegradable microplastics and demonstrates that integrating SEM enables high-resolution, direct observation of their degradation process. These findings contribute to a deeper understanding of how biodegradable materials break down under realistic biological conditions. Furthermore, this study offers strategic insights into the design and application of sustainable plastics, contributing to the global effort to mitigate microplastic pollution.