[aifooh7Keew6xoo]

It's actually referred to as a bioplastic in the linked Wikipedia article and is a solid, polymerizing organic molecule with "plastic"-like properties -- and, apparently, known biological activity.

I think it's a valid question that its status as not being petroleum derived does not necessarily answer meaningfully.

[instagib]

From the wiki article.

“Once discarded, chitosan-constructed objects are biodegradable and non-toxic.[66] … Pigmented chitosan objects can be recycled,… Unlike other plant-based bioplastics (e.g. cellulose, starch)”

[westurner]

Aren't there [proton,] batteries made of Chitosan; Proton-Polymer batteries?