What materials, produced naturally by bacteria as energy storage reserves, are considered perhaps the earliest true biodegradable plastics?

Answer

Poly-hydroxyalkanoates (PHAs)

Poly-hydroxyalkanoates (PHAs) are polymers created by living organisms themselves, functioning as energy storage reserves within bacterial cells, making them among the earliest materials fitting the true definition of biodegradable plastic.

What materials, produced naturally by bacteria as energy storage reserves, are considered perhaps the earliest true biodegradable plastics?
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