The use of inorganic acids, such as hydrochloric acid, to hydrolyze sucrose to glucose and fructose is known to those skilled in the art. An illustrative process is described in published U.S. application 2004 0231662 to De Mendonca Ferreira et al. The prior art has generally focussed on enzymatic hydrolysis of sucrose to produce glucose and/or fructose as evidenced by U.S. Pat. Nos. 5,998,177 and 6,660,502 to Catani et al.

Succinic acid(cas:110-15-6) is an organic acid with two carboxylic groups. It is produced today mainly petrochemically from butane through maleic anhydride. Succinic acid(cas:110-15-6) is currently a low volume chemical. By production of succinic acid(cas:110-15-6) using biomass instead of petrochemicals as raw material, many new applications are possible. The production does not contribute to the accumulation of greenhouse gases since the feedstocks are renewable. A report from the U.S. Department of Energy designates succinic acid(cas:110-15-6) as a top twelve building block chemical produced from biomass (Werpy T., et al., Top Value Added Chemicals from Biomass. U.S. Department of Energy: Oak Ridge (2004)). Succinic acid(cas:110-15-6) can be used as a commodity or specialty chemical according to the report. As a commodity chemical it can substitute chemicals based on benzene and other intermediate petrochemicals to for instance produce polyester, solvents and other acids. Food ingredients, fuel additives and environmentally benign deicers are examples of specialty chemicals from succinic acid(cas:110-15-6). The feedstocks of interest for producing succinic acid(cas:110-15-6) contain starch, hemicellulose or cellulose and can come from agricultural residues like corn fibres, forest products or beat and cane sugar.

Fermentation can be accomplished with a number of different organisms. E. coli mutant AFP184 (described elsewhere) is used. The sugar available in sugar beet or cane is sucrose. It is a disaccharide of glucose and fructose. E. coli are not able to utilize sucrose, but can utilize glucose and fructose. Therefore, it is necessary to hydrolyze the sucrose before fermentation. Hydrolysis is normally performed with concentrated or dilute mineral acids. These acids are added to the process and require separate and costly recovery processes.

Bacteria which enable the production of succinic acid(cas:110-15-6) are well known. Examples are U.S. Pat. No. 6,265,190 to Yedur, U.S. Pat. No. 6,743,610 to Donnelly et al. This acid has not been used for the production of glucose and fructose.

OBJECTS

There is a need for an improved process for the preparation of glucose and fructose from sucrose. It is therefore an object of the present invention to provide a process for hydrolysis of sucrose which uses unique acid hydrolysis step for producing glucose and sucrose. It is further an object of the present invention to provide a unique hydrolysate which can be used for fermentation processes. Further still, it is an object of the present invention to provide a process for the isolation of pure glucose and fructose. Further still, it is an object of the present invention to provide a process which provides high yields and is economical. These and other objects will become increasingly apparent by reference to the following description and the drawings.

SUMMARY OF INVENTION

The invention provides a process which uses succinic acid(cas:110-15-6) to hydrolyze (invert) sucrose into fructose and glucose. The resulting sugar mixture is then used as the substrate for an E. coli or other bacterial fermentation to produce succinic acid(cas:110-15-6) or other organic compounds. The process is novel in that: a) it uses succinic acid(cas:110-15-6) for sucrose hydrolysis, which has not been previously demonstrated, and b) the resulting sugar mixture can be fermented by succinate producing organisms that are otherwise unable to produce succinic acid(cas:110-15-6) from sucrose. If it is desired to recover the succinic acid(cas:110-15-6), it can be accomplished in the same process used for the purification of the fermentation broth to produce pure succinic acid and there would be no need for building a new recovery plant.

Thus the present invention relates to a process for producing glucose and fructose which comprises:

hydrolyzing a composition comprising sucrose in an aqueous solution with succinic acid to produce glucose and sucrose in a hydrolysate. Preferably the hydrolysis is at a temperature between about 25° C. and below a boiling point of the solution. Preferably the temperature is between about 60° and 100° C. Preferably the sucrose is at a weight ratio of between about 10 to 1 to 1 to 10 in the aqueous solution. Preferably the sucrose is at a weight ratio of between 1 to 10 and 4 to 10. Preferably the succinic acid is at a concentration between about 0.1 and 10 percent by weight in the aqueous solution. Preferably the succinic acid(cas:110-15-6) is at a concentration of 0.5 to 5% by weight of the aqueous solution. Preferably the glucose and fructose are produced at a yield above 95% by weight based upon a weight of glucose and fructose available in the sucrose. Preferably the hydrolysis is over a time period of up to about 24 hours. Preferably in addition the hydrolysate is fermented by a microorganism which metabolizes the glucose and fructose to produce a fermentation product. Preferably the microorganism produces succinic acid(cas:110-15-6) from the hydrolysate as the fermentation product. Preferably the microorganism is an Escherichia coli strain.

The present invention also relates to a fermentation process wherein a microorganism ferments a carbohydrate to produce a fermentation product, the improvement which comprises fermenting a succinic acid(cas:110-15-6) hydrolysate of a composition comprising sucrose to produce the fermentation product. Preferably the fermentation product is succinic acid(cas:110-15-6) and the microorganism is an Escherichia coli strain which with the carbohydrate produces succinic acid.