PLA (polylactic acid) is made from sugars in cornstarch, cassava, or sugarcane, and it is biodegradable, carbon-neutral, and edible. The process of corn into plastic is corn kernels absorb sulfur dioxide and hot water, which breaks down into starch and fiber. The kernels are ground and the oil is separated (usually used for food packaging)
"The starch is comprised of long chains of carbon molecules, similar to the carbon chains in plastic from fossil fuels. Some citric acids are mixed in to form a long-chain polymer (a large molecule consisting of repeating smaller units) that is the building block for plastic"