Process for preparing L-rhamnose.

摘要

This invention relates to a process for readily and efficiently preparing L-rhamnose with the use of a marine alga belonging to the family Monostromaceae, Ulvales. According to the process of the present invention, rhamnan sulfate is extracted from a marine alga belonging to the family Monostromaceae such as Monostroma nitidium Wittrock and the obtained extract is hydrolyzed by adding acid(s) thereto followed by heating or treating thereof with a cation exchange resin followed by heating to thereby give a solution containing free L-rhamnose. Since the solution thus obtained contains a large amount of salts, the removal of these salts is significantly important in the preparation of L-rhamnose. In the present invention, an effective process therefor is combined with a conventional method by using an ion exchange resin to thereby establish an efficient desalting process. Further it is effective to elevate the purity of L-rhamnose by adding baker's yeast, which selectively ferments various sugars, to the solution containing L-rhamnose. The present invention makes it possible to economically prepare L-rhamnose. Thus a large amount of the same can be supplied as a raw material to the fields of pharmaceuticals, agricultural chemicals and food.