Potential for biodegradation of microplastics in thermophilic anaerobic digesters

Microplastics have emerged as new environmental pollutants. In this study biodegradation of polypropylene under thermophilic conditions were observed to be several orders higher than in any other environment investigated previously. A series of imaging AFM and SEM revealed presence of oxidation products accumulated on the surface, while spectroscopic analysis of the extracted and concentrated products were analysed by FTIR, Raman and NMR. The spectroscopic analysis revealed important insight into the composition, and a model of the polymer breakage involving formation of integrated cis-configured double bonds (olefins). The findings show a high potential for biodegradation of (micro)plastic in conventional ADs. The results furthermore support the use of applying anaerobic digesters for the treatment of highly energetic household waste with a high content of plastics.