Carbohydrates large-scale production

Some of the economic hurdles and process cost centers of this conventional carbohydrate fermentation process, schematically shown in Eigure 1, are in the complex separation steps which are needed to recover and purify the product from the cmde fermentation broths. Eurthermore, approximately a ton of gypsum, CaSO, by-product is produced and needs to be disposed of for every ton of lactic acid produced by the conventional fermentation and recovery process (30). These factors have made large-scale production by this conventional route economically and ecologically unattractive. 

Fermentative Manufacture. Throughout the years, riboflavin yields obtained by fermentation have been improved to the point of commercial feasibiUty. Most of the riboflavin thus produced is consumed in the form of cmde concentrates for the enrichment of animal feeds. Riboflavin was first produced by fermentation in 1940 from the residue of butanol—acetone fermentation. Several methods were developed for large-scale production (41). A suitable carbohydrate-containing mash is prepared and sterilised, and the pH adjusted to 6—7. The mash is buffered with calcium carbonate, inoculated with Clostridium acetohutylicum and incubated at 37—40°C for 2—3 d. The yield is ca 70 mg riboflavin/L (42) (see Fermentation). 

In addition to enhancement with essential vitamins, amino acids, and proteins, plants can also be metabolically engineered to produce nutritionally superior carbohydrates and lipids. The relative inexpensiveness as well as the capability to grow large-scale quantities make plant production an attractive feature. In the case of carbohydrates such as starch and sucrose, many products or modifications of these products can be produced on a large scale and at much lower costs than are currently available. For example, trehalose, a food additive, was in the past too costly for large-scale production however, it has now been produced in transgenic tobacco tissue at a much reduced cost. 

After preparation of this review, an abstract by Godde A, Kragl U, Biselli M, Katapodis A, Bowen BR, Ernst B, Wandrey C, was published on the XVIIIth International Carbohydrate Symposium, July 21-26, 1996, Milano, Italy (BP 135, p 390). It reports the large-scale production of 1800 units of a recombinant human al-3 fucosyltransferase (FucT VI, EC. 2.4.1.152) in its soluble form with a CHO cell line in a continuous fermentation process in a fluidized bed reactor (34mUmg 1 in culture supernatant). After partial purification the specific activity yielded 220 mU mg ... 

Endo T, Koizumi S, Tabata K, Kakita S, Ozaki A. Large-scale production of W-acetyllactosamine through bacterial coupling. 90. Carbohydr. Res. 1999 316 179-183. 

Koizumi, S. (2005). Large-scale production of oligosaccharides using engineered bacteria. In Handbook of Carbohydrate Engineering, K. J. Yarema, ed. CRC Press/Taylor Francis, Boca Raton, FL, pp. 325-338. 

In the past decade there has been significant progress in development of carbohydrate-based therapeutics. Also, new methods for the large-scale production of carbohydrates and their analogs are allowing the thorough evaluation of their safety and efficacy in human trials. 

Conventional fermentative production of carbohydrates has received considerable attention, particularly with respect to the use of xanthan as an adjunct to oil-well drilling. Biochemists and chemists are becoming increasingly aware of the potential of immobilizing whole microbial cells for the large-scale production of a wide variety of molecules. 

These carbohydrate derivatives, including the oligosaccharides, are intriguing potential structures for cationic systems and ultimately ionic liquids owing not only to their particular structural characteristics, but also to their ready availability for large scale production. 

Maru, 1., Ohnishi, J., Ohta, Y., Tsukada, Y. Simple and large-scale production of N-acetylneuraminic acid from N-acetyl-D-glucsamine and pyruvate using N-aceyl-D-glucosamine 2-epimerase and N-acetylneuraminate lyase. Carbohydr. Res., 1998, 306, 575-578. 

Despite not being a large scale product, rising production and decreasing prices will enhance numerous new special applications. Developments that will lead to ->c. derivatives and ->c. polymers are indicative for the extending carbohydrate discipline of CD-chemistry . 

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