[smsm42]

Bacteria can do pretty much any chemistry that's within their energy reach. E.g. making sugars out of plastics. Or ethanol. Or anything else. There's no law that says it has to be all water and co2. I see no argument why it can't be partial - enzymes do partial degrading alk the time.

[ars]

It's because if you are digesting plastic for energy, you pretty much can't make anything else out of it.

Like you said, energy reach.