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Marine biodegradation of tailor-made polyhydroxyalkanoates (PHA) influenced by the chemical structure and associated bacterial communities

npj Emerging Contaminants 2023 27 citations

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Scientists tested how well different types of "biodegradable" bioplastics (called PHAs) actually break down in ocean water, and found that both the plastic's chemical makeup and the specific bacteria living on it determine how fast it disappears. This matters because not all biodegradable plastics break down at the same rate in nature, so knowing which formulas degrade best could help reduce ocean plastic pollution and the microplastics that eventually end up in our food and water.

Over recent years, biodegradable polymers have been proposed to reduce environmental impacts of plastics for specific applications. The production of polyhydroxyalkanoates (PHA) by using diverse carbon sources provides further benefits for the sustainable development of biodegradable plastics. Here, we present the first study evaluating the impact of physical, chemical and biological factors driving the biodegradability of various tailor-made PHAs in the marine environment. Our multidisciplinary approach demonstrated that the chemical structure of the polymer (i.e. the side chain size for short- vs. medium-chain PHA) which was intrinsically correlated to the physico-chemical properties, together with the specificity of the biofilm growing on plastic films (i.e., the associated 'plastisphere') were the main drivers of the PHA biodegradation in the marine environment.

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