Microbially Produced Rhamnolipid as a Source of Rhamnose

Abstract

The sugar L-rhamnose (6-deoxy-~-mannose) is used as a fine chemical in scientific and industrial settings, as a component in chemical reactions, and as a starting material in the synthesis of organic compounds. Present methods for the commercial preparation of rhamnose require extrac- tion of quercitrin from oak bark, naringin from citrus peels, or rutin (quercetin-3-rutinoside) from oak bark or a variety of plants, such as buckwheat.’.‘ Quercitrin is a gly- coside made up of the aromatic aglycone quercetine and rhamnose, whereas naringin and rutin are glycosides con- taining a glucose moiety in addition to rhamnose and the aglycone. Rhamnose is recovered by the hydrolysis of these molecules. Several disadvantages accompany the labor-intensive processes for production of rhamnose from quercitrin, naringin, and rutin, including the production of large quantities of potentially toxic, aromatic waste prod- ucts and the need for toxic or corrosive chemicals in the extraction process. Furthermore, the bulky raw materials used for extraction must be harvested and then either trans- ported at some expense to the extraction facility, or the processing plant must be located in proximity to the raw materials