Degradation of conventional and biodegradable microplastics in the marine environment

Nuria Fernández de Villalobos

Plastics, and more particularly microplastics (<5 mm), have now reached every corner of the world, hence being in the spotlight of different stakeholders. Because of their small size, microplastics can be sequentially ingested by aquatic organisms along the entire food chain, posing an enormous threat to the aquatic life. Low-density polyethylene (LDPE) and polyethylene terephthalate (PET) are two of the most produced plastics worldwide. Several studies have identified microbial strains with the potential to colonize and/or bio-deteriorate these polymers, although their complete degradation has not been proved so far. Biodegradable plastics seem to be a promising alternative to conventional synthetic plastics. However, their biodegradability is limited to specific environmental conditions. Hence, it is urgently needed to find ways to degrade both synthetic and biodegradable polymers. For these reasons, this study assesses the biodegradability of LDPE and “biodegradable” PET using bacterial communities recovered from marine caves in southern Portugal. After an incubation period of 45 days with the bacterial consortium, both polymers presented biodegradation signs, mainly observed through Attenuated Total Reflectance-Fourier Infrared spectroscopy (ATR-FTIR) and scanning electron microscopy (SEM).