Synthesis of L-Tagatose for use as a Therapeutic Agent

L-tagatose might be even more effective than D-tagatose in treatment of atherosclerosis and diabetes. There are several routes to the L-form:

• 1. Chemical isomerization of L-galactose to L-tagatose in alkali conditions, analogous to isomerization of D-galactose to D-tagatose (Spherix’s recently expired patent).

  2. L-galactose might be isomerized to L-tagatose enzymatically with fucosic isomerase, although in publications there is some reverse reaction to produce L-galactose as one of the stages of ascorbic acid production.

  3. Biotransformation of L-psycose to L-tagatose with use of Enterobacter aerogenes.

  4. Biotransformation of galactitol to L-tagatose with use of Klebsiella pneumoniae.

  5. Enzymatic production of L-tagatose from galactitol with use of galactitol dehydrogenase.

  6. Epimerization of L-sorbose to L-tagatose with use of the 3-epimerase of D-tagatose.

In most cases described, the problem is that substrates are not naturally available or are existing in very low amounts and they need to be produced in complicated procedures. Students working on this project are focusing on epimerization of L-sorbose. L-sorbose is produced from D-sorbitol with use of Gluconobacter oxydans. The technology is well developed because L-sorbose is the substrate for ascorbic acid production.