A study led by Juan M. Lema, researcher at CRETUS (Universidade de Santiago de Compostela), together with researchers Guangqing Liu and Chang Chen from the Beijing University of Chemical Technology (BUCT), shows that certain biodegradable plastics can fragment and generate persistent microplastics.
Biodegradable plastics (BPs) are progressively replacing conventional plastics in everyday products such as bags, packaging and agricultural materials. Many of these materials are designed to degrade under controlled conditions, such as industrial composting. However, their degradation behaviour and their potential to generate microplastics in oxygen-free (anaerobic) environments remain unclear.
Published in Environmental Science & Technology, a leading journal in environmental science and engineering, the study examines the behaviour of these materials under anaerobic conditions, such as those found in landfills, sediments and waste management systems, including wastewater treatment plants.
The findings reveal that, under such conditions, the degradation of some bioplastics may be incomplete, leading to fragmentation into microplastics that can persist in the environment.
The research team has also developed new analytical methods to identify, quantify and monitor the evolution of microplastics generated from different types of bioplastics under anaerobic conditions. The results demonstrate that the chemical structure of polymers determines their behaviour. While some bioplastics such as PHB, PHBV or CDA show high biodegradability, others such as PBAT, PBS or PCL exhibit very limited biodegradability, despite fragmenting and releasing microplastics that remain in the environment.
These findings challenge the widespread assumption that all bioplastics are a definitive solution to plastic pollution and highlight the need to assess the behaviour of each material under real environmental conditions.
First scientific collaboration between CRETUS and BUCT
This work also has significant strategic value, as it represents the first scientific collaboration between the Centre for Cross Disciplinary Research in Environmental Technology (CRETUS), a CIGUS Network centre co-funded by FEDER (EU) funds, and the Beijing University of Chemical Technology, an internationally recognised institution in the field of chemical engineering.
The collaboration, which began in 2025 through an agreement between the two institutions and already includes several ongoing projects, strengthens CRETUS’s international profile and opens up new avenues for scientific cooperation in sustainability and advanced materials.
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