We need to isolate and start selectively breeding the plastic eating bacteria so we can optimise their efficiency, and then somehow splice their DNA into the gut bacteria of an obligate carnivore, so we can put it in our cats gut biomes so they'll finally be free of having to choose between whether they want to eat plastic or whether they want to live.
As a geneticist and microbiologist who has worked with plastic-degrading microbes briefly, this is theoretically possible. The most difficult parts would be finding a microbe that could take plastic in it's unaltered (or slightly stomach-acid degraded) form.
For my project, we were trying to identify microbes that could use partially treated plastic as a food source and break it down further. The carbon bonds in our daily plastics are really hard to get at and break, hence the bad degradation, so breaking some of those bonds through heat and chemicals first can help microbes get access to them. Once we identify a microbe that can do this, we could test giving them slightly less degraded plastic to live on until they develop a way to eat it and go until they either get back to normal plastic or hit a wall where the microbe can't progress anymore (which may be likely).
An alternative approach to breeding (although you don't 'breed' most microbes since they reproduce asexually but instead find strains with mutations that lead to desired changes) would be trying to predict an enzyme that could break the bonds in plastic, engineering it, and putting it in microbes to test if it works. On one hand it could overcome any natural halt selection has but would be initially harder to discover.
The best solution would probably be to find the microbe that can eat the partially degraded plastic, figure out what enzyme is doing the work, then see how the enzyme could be improved to work through plastic in its default state.
Once you have that, the next consideration would be what byproducts are created from eating plastic? Part of the project was hoping that the microbe that could eat plastic would produce a useful byproduct that could be harvested, as an unfortunate reality of our current world is that if it's not profitable it probably won't take hold. But if we wish to put this in a living organism, we need to make sure it won't produce a harmful byproduct, or if it does, then ensuring the organism can quickly turn it harmless before it builds up.
Once all of that is figured out, the next hardest thing would be ensuring that whatever gut microbe you put the plastic eating gene in continues to express it. Since plastic is so hard to use it would probably prefer to use any glucose lying around first, and if that runs out then switch to eating plastic. We could try removing its ability to eat glucose (or whatever other compounds it lives off of), but then it would be less competitive in the gut environment and would require a steady source of plastic in order to not die off.
Although, I assume cats (and some people) would not find that a challenge.
...holy shit.
the only research I did for this post was 30 seconds to double-check on wikipedia whether or not bacteria have DNA.
