system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How valid are claims of “plastic eating bacteria”; is this media-overhype?

If not, how does this work?

Thanks in advance.
gpt
The plastic that you typically hear about in terms of pollution is polyethylene and polypropylene, which combined account for the majority of global plastic production.  Those are what make up all the cheap plastic garbage that gets dumped into the ocean - things like plastic bottles, bags, and straws are all made out of polyethylene or polypropylene.

Thus far a few fungi and bacteria have been found that can degrade the "soft" versions of those plastics under perfect laboratory conditions.  They aren't actually "eating" the plastic - they're just degrading it, and it doesn't necessarily degrade into stuff that's more environmentally friendly than plastic to begin with.

They typically can't degrade those plastics at all if they've been hardened, which most plastic is.

Under real world conditions, the rate that they degrade those plastics is so slow that it might as well not be happening and other processes, like photo-degradation, are responsible for the bulk of degradation even when those fungi and bacteria have been deliberately cultivated on the plastic.

There is a bacteria that can actually eat polyester - although polyester only accounts for about 15% of global plastic production.  And, again, it can only eat the soft version of that plastic - while most polyester is hardened - and even then it eats the soft polyester very slowly under laboratory conditions.

There is some hope that the enzymes responsible for degrading plastics may be able to be fine tuned with genetic engineering, but we're still a long way from being able to turn that into something that can break down plastic in a meaningful way.