Sorbitol, economics

Most current industrial vitamin C production is based on the efficient second synthesis developed by Reichstein and Grbssner in 1934 (15). Various attempts to develop a superior, more economical L-ascorbic acid process have been reported since 1934. These approaches, which have met with htde success, ate summarized in Crawford s comprehensive review (46). Currently, all chemical syntheses of vitamin C involve modifications of the Reichstein and Grbssner approach (Fig. 5). In the first step, D-glucose (4) is catalytically (Ni-catalyst) hydrogenated to D-sorbitol (20). Oxidation to L-sotbose (21) occurs microhiologicaRy with The isolated L-sotbose is reacted with acetone and sulfuric acid to yield 2,3 4,6 diacetone-L-sorbose,... 

U.S. 6,649,754 (to Merck) describes a process for making mannitol by hydrogenation of a mixture of glucose and fructose. U.S. 3,632,656 (to Atlas Chemical) describes recovery of mannitol from a mixture with sorbitol by crystallization from aqueous solution. U.S. 4,456,774 (to Union Carbide) describes an adsorptive separation of mannitol from sorbitol. U.S. 6,235,947 (to Takeda Chemical Industries) describes a process for recrystallizing mannitol to improve the crystal morphology and hence make a more compressible product that can be used in making tablets. Estimate the cost of production of Mannitol by the Merck route and determine which separation is most economical. What is the additional cost of making the recrystallized product via the Takeda route ... 

Use S. is the economically most important sugar compound and is produced in larger amounts for further use as an industrial feedstock, see also Lit. . Besides its main use in the food industry and for conservation purposes (jams, etc.), S. can also be used in plastics, varnishes, as fermentation additive for the production of proteins, amino acids, yeasts, enzymes, antibiotics, steroids, fats, ethanol, ethylene, glycerol, sorbitol, sugar acids, explosives, tartaric acid, softeners, saccharose esters for detergents, etc. S.-propylene oxide adducts are used in hard PUR expanded plastics. 

Until now, other L-sugars have been available only in small amounts. It is assumed that they are metabolized not at all or only to a small extent by human beings and even in low concentrations, they are capable of inhibiting the glycosidases of the small intestine. Therefore, economic methods of synthesis are of interest. A suitable educt is L-arabinose, which yields a L-glucose/L-mannose mixture by chain extension. This mixture can be oxidized directly to L-fructose or after reduction via L-sorbitol/L-mannitol. The isomerization of L-sorbose to L-idose and L-gulose is also under discussion. 

Jemsalem artichokes contain high amoxmts of inulin (fructose), which can yield above 0.259 g/g (gram of product produced per gram of sugars consumed) of sorbitol (Duvnjak et al., 1991). A drawback of this process is the comparatively elevated price of Jerusalem artichokes as a juice source. Consequently, they are not suitable for tire economic production of fructose. 

Additionally, in this work high concentrations of yeast extract were used, which is expensive and thus an important negative cost factor for the economic production of sorbitol. Among potential candidates for sorbitol bioproduction, the bacteria Zymomoms mobilis is very popular due to its enzyme glucose-fructose oxidoreductase, which is able to convert fructose and glucose to sorbitol and gluconolactone (shortly converted to gluconic acid Zachariou et al., 1986). 

A further economically viable way of producing sorbitol is the use of cheap media, such as CSL, a cheap source of vitamins and nitrogen, to obtain high bioconversion (Silveira et al., 2001). In this case, the process was carried out in a batch mode. Using 25g/L of CSL instead of 5g/L of yeast extract, the costs for the medium can be reduced between 25% and 50%. 

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