Source: Chemical Market Reporter
A manufacturing challenge in amino acids was solved earlier this year by Wacker-Chemie, Germany, which has developed a fermentation technology for making L-cysteine. Wacker Biochem Corp., the U.S. biotech venture of Wacker, partnered with Kyowa Hakko USA, a leading marketer and producer of amino acids, to market and sell Wacker-produced cysteine in the U.S.
The fermentation technology is a significant breakthrough for manufacturing L-cysteine. Up to now, cysteine has mostly been extracted from raw materials of animal and human origins. It is mainly obtained from human hair, and to a lesser extent, from feathers, pigs' bristles and hooves. The horny substance, known as keratin, is rich in cystine, which consists of two molecules of cysteine joined by a disulfide bridge.
To develop a bacterial strain with which cysteine can be produced by fermenting renewable raw materials, Wacker used the bacterial strain Escherichia coli and dextrose as a starting material. By way of metabolic design, for which Wacker has four basic patents, the process overrides the natural mechanism that regulates cysteine synthesis. The new approach, according to Wacker, does not necessitate introducing a foreign gene into Escherichia coli , but consists, as in the conventional selection of microorganism, simply in optimizing genes already present in the bacterium. "Instead of producing just enough cysteine to cover its own needs, the optimized E. coli strain also release large quantities into the nutrient medium, where it oxidizes in the presence of atmospheric oxygen to cystine, which crystalline out," explains Gerhard Schmid, president of Wacker Biochem.
Wacker is starting up production for cysteine at fermentation facilities in Europe, where capacity is available for commercial quantities, says Dr. Schmid. The use of dextrose as a starting material makes for a cost-efficient process and the non-animal based material is also an improvement over the traditional methods of producing cysteine, he adds.
For Kyowa Hakko, the Wacker alliance allows the amino acid producer to now offer the full range of amino acids. "This alliance certainly allows for synergies between Kyowa and Wacker Biochem," says Donald Blaine, general manager for Kyowa Hakko's marketing arm, Kyowa Hakko USA, Inc. This is the first such alliance for Kyowa in amino acid manufacture, which makes the full range of amino acids.
Within the food industry, cysteine is used primarily in the production of reaction flavors for foods and pet foods to improve savory flavors, as an antioxidant, and as a natural dough conditioner, according to SRI Consulting, Menlo Park, California. In the U.S., n-acetyl cysteine is one of the amino products used in dietary supplements.
Overall world demand for cysteine is expected to grow 2 to 3 percent per year through 2002, to reach 4,400 to 4,600 metric tons. Western European demand for cysteine will increase at an average annual rate of 3 to 4 percent through 2002, driven primarily by increasing use in food and pet applications, estimates SRI, and Japanese demand is expected to increase 2 percent through 2002.
Wacker's Dr. Schmid says the fermentation route for cysteine could offer further development in fine chemical manufacture, where the route could be applied to the synthesis of unnatural amino acids.
By Patricia Van Arnum
Copyright © 2001 Schnell Publishing Co. Reprinted with permission.