Bioplastics or organic plastics are derivied from renewable sources such as starch, vegetable oil and even chicken feathers.
Some bioplastics, like the one made from chicken feathers, do biodegrade.
Others, like the plant derived PET used by Coke, do not. In fact it shares the same long lasting, non biodegradable qualities as petroleum derived PET.
YET The term bio-plastics is used to describe both types of plant derived plastic ie biodegradable and biomass derived.
This has led to CONFUSION
In short, just because a plastic has been made from plants does not mean it is biodegradable.While not all plant based plastics are biodegradable, these are
Polyhydroxyalkanoates or PHAs ( taken from Wikipedia) : are linear polyesters produced in nature by bacterial fermentation of sugar or lipids. They are produced by the bacteria to store carbon and energy.