The present invention provides a biodegradable polymer composition useful for manufacturing biodegradable in which, the process comprising: (1) providing a renewable polymer and/or natural fiber having: (a) a T.sub.s value of up to about 90.degree. C.; and (b) a heat distortion index of up to about 90.degree. C.; (2) providing a heat-resistant polymer having: (a) a T.sub.s of greater than about 60.degree. C.; and (b) a heat distortion index greater than about 50.degree. C., wherein the T.sub.s value and heat distortion index of the heat-resistant polymer is greater than that of the renewable polymer and/or natural fiber; and (3) coextruding the heat-resistant polymer and the renewable polymer to provide a thermoformable composite comprising a core comprising the renewable polymer and/or natural fiber, wherein the renewable polymer and/or natural fiber comprises at least about 50% by weight of the composite and a heat-resistant outer layer comprising the heat-resistant polymer which substantially surrounds the core.