In 2012, Nature revealed that humans provide a home to thousands of different species of microbes in a series of papers that opened a path to understanding the impact of the human microbiome on our health.
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I imagine anything that evolved naturally to not have a huge impact because being able to suggest various plastics doesn’t confer enough of an evolutionary advantage to invest in it.
However we’re already searching for and breeding for much more efficient organisms to be used in bio reactors for recycling purposes[1].
So of a particular effective variant, whatever the origin, were to be able to break down plastic before it’s discarded things could get interesting. Thinking of pipes, bags, package linings, clothes, etc. It’s a lengthy list.
1: https://sciencesensei.com/the-bacteria-that-eat-plastic-waste-are-evolving-faster-than-expected/