Manufactured regenerated fibers are made from the chemical-induced transformation of natural polymers and basically fall into two categories: protein origin and cellulose origin. Regenerated fibers of protein origin come from plant protein (such as corn, soy, alginate, and peanut), or from animal protein (such as casein from milk). Many of the new, hot eco-friendly fabrics – like Ingeo from corn and soy from soybeans – are manufactured from proteins found in plants.