Current biodegradable plastics are an industry smokescreen. The biodegradable portion is generally plant starch used as a binder. The “plastic” is just that, a very stable long lived micro/nano plastic. The big chunks break down, and the plastics continue to move through the environment and bioaccumulate.

The work towards truly biodegrade plastic is generally from the other end; identifying or making organisms that can break down the polymers themselves. Those don’t seem to be commercially viable, and in themselves won’t address environmental plastic pollution.