Biodegradation assessment of polymer-based films by bacterial species in the marine environment and its correlation with microplastic production and toxicity

The advantages of polymeric materials have been supplanted by the problem of anthropogenic litter in the oceans. Ideal materials that combine suitable properties for use and minor environmental impact after discard motivate the research and engineering of new polymers, blends, and composites. Aiming to understand the correlations of polymer biodegradation, marine toxicity and microplastic formation, this research evaluated five polymer-based films (varied polymers, blends, and fillers) regarding their biodegradability in natural and synthetic marine media. The experiments were monitored through CO evolution, correlating the results with bacteriological (bacteria species and couting), chemical (Raman spectra), and physical data. The remained media was subjected to toxicity assessment, and the microplastic produced by the samples´ biodegradation was collected and analysed. Even though most of the polymeric-based films achieved the biodegradability requirements (over than 80 % within 90 days), toxicity (maximum dilution of 32 time for all biodegradation products in natural media) and microplastic formation (between 10 and 130 microparticles) were expressive, particularly for polylactic acid-based samples. All in all, the results with natural marine water pointed out that there is still no ideal polymeric-based material that produces no environmental impact after the release in the oceans and biodegradation by waterborne bacteria.