Lactic acid can be produced by fermenting sugar from grain or other organic matter. Lactic acid can be polymerized to produce a linear aliphatic polyester, polylactic acid (PLA). The degradation of PLA is divided into two stages. The first stage is that its ester group is gradually hydrolyzed to lactic acid and other small molecules, and then these small molecules are decomposed by microorganisms in the environment PLA is often blended with starch to enhance its degradability and reduce its cost. However, this blend product is too brittle, so some plasticizers such as glycerin and sorbitol are often added to make it softer. Some producers often use other degradable polyester to blend with PLA to replace plasticizers PLA material has a smooth surface and high transparency, so it can compete with polystyrene and pet in some application fields. PLA film has been used in the hard packaging of fruits and vegetables, eggs, cooked food and baked goods. PLA film is being used in the packaging of sanneimingzhi, biscuits, flowers and other commercial products. PLA is also blown into bottles for packaging water, soup, food and edible oil Some automakers, most notably Toyota in Japan, are working on the application of PLA and other biodegradable plastics to uncoated cars