L-Aspartic acid is the L-form of the aspartic acid. It is one of the 20 amino acids that used in the protein synthesis. It is the non-essential amino acids for humans as it can be synthesized in vivo. It is important in the synthesis of other amino acids and some nucleotides, and is a metabolite in the citric acid and urea cycles. In animals, it may be used as a neurotransmitter. It can be chemically synthesize from the diethyl sodium phthalimidomalonate. Currently, almost all the aspartic acids are manufactured in China. Its application include being used as low calorie sweetener (as the part of the aspartame), scale and corrosion inhibitor, and in resins. One of its growing applications is for the manufacturing of biodegradable superabsorbent polymer, polyaspartic acid. It can also be used in fertilizer industry to improve water retention and nitrogen uptake.