Why not PLA? These are semi common and other than being a bit more brittle than plastic are otherwise indistinguishable.

Reading an article, apparently a hassle without industrial composting. It so happens San Francisco has that, so it works very nicely. If you get a PLA straw and cup, whole spent thing goes in the green bin. Kind of neat.

PLA *is* a plastic, not a comparator. And PLA, while a clever and useful material, is not actually biodegradable outside of a composting reactor.