^ Above is the process before fermentation. It involves the bacteria being grown in order for the correct amino acids to be produced. The bacteria used are B. Flavum and C. Glutamicum
Considering aspartame is an artificial sweetener and is composed of amino acids; aspartic acid and phenylalanine, many steps have to be taken in order to synthesize the physical form of aspartame. The main steps to make aspartame are:
Fermentation (Bacteria is raised to produce the amino acids)
Synthesis (Amino acids are modified to leave a crystalline residue behind)
Purification (Removing residue to present aspartame)
Fermentation This process is the key to making aspartame. This process involves the use of bacteria. Before fermentation, a group of bacteria is tested within a test tube containing the various nutrients it needs in order to survive. After this step, the bacteria continue to multiply. When the approximate population are met, the bacteria are then transferred to a seed tank where they are used to create aspartic acid and phenylalanine. Within the seed tank, more bacteria is grown. This is because the seed tank serves as an ideal habitat for the bacteria; it contains the various nutrients to thrive beyond even more. The seed tanks are filled with warm water, molasses, glucose, and sucrose. Other sources include acetic acid, alcohol, hydrocarbons, and different sources of nitrogen such as liquid ammonia and urea ( a clear crystalline composed from the main nitrogen breakdown of products from mammals that is excreted within urine). The tank also comes with a mixer that keeps the growth pattern going, and a pump, which brings compressed air into the tank. When enough bacteria is produced, materials from the seed tank are then pumped into the fermentation tank. Fermentation tanks are larger versions of seed tanks. They come with the same materials as the seed tank have. Within this tank, the bacteria produce mass quantities of amino acids in order to make aspartame. Control of the pH levels are crucial within this stage, so the ammonia water is added within the tank when needed. When the amount of amino acid required is met, materials within the fermentation tank are brought out into isolation. During this process, a centrifugal separator is required to separate large proportions of the amino acids produced by the bacteria. The "wanted" amino acids are then isolated and separated and purified in a ion-exchange column. Within this column, the amino acids are transferred to a crystallization tank, and then to a crystal tank. The amino acids are then dried and are ready for the synthesis stage for the production of aspartame.
^ Above is the Synthesis process of aspartame, where the amino acids are modified and readied for purification for the final result
Synthesis Phenylalanine gets modified by a reaction with methanol and is then combined with modified aspartic acid. This forms a compound called L-phenylalanine methyl ester. Aspartic acid can be modified to even protect numerous parts of the molecule from more reactions. One method is by reacting the aspartic acid with substances that result in added benzyl rings to protect these sites. This makes chemical reactions occur only on specific parts of the aspartic acid molecule. After that the amino acids are modified, pumped into a reactor tank, and they are mixed at room temperature for 24 hours (one day). The temperature is later increased to 149°F (65 °C) and maintained for another 24 hours. The reaction is then cooled to room temperature. This substance is carefully diluted with a solvent and cooled to about 0°F (-18°C), forming crystals. The crystals are isolated to filtration and dried. These crystals must be reacted with acetic acid by filling a tank with acid made from palladium metal catalyst and hydrogen. It is mixed with these crystals and allowed to react for 12 hours.
Purification The liquid is then distilled and the liquid is carefully extracted. This leaves a solid residue which can be purified with a liquid ethanol solution and is formed back into crystals. These crystals are finally filtered and dried until they create the aspartame powder. This is a long process but has mass productions, making this hard long process easier. The powder is at last stored in tiny packets and distributed around the world.
< On the left is a sample of C. Glutamicum. This bacteria is used to produce the amino acid phenylalanine, an essential amino acid in aspartame
< On the right is a sample of B. Flavum. This type of bacteria is used to produce the amino acid, aspartic acid, and essential acid in the making of aspartame.