| The manufacture of aromatic molecules by the chemical industry relies on the use of benzene, toluene, and o, m, or p-xylenes as the starting material. These aromatic starting materials are obtained from the BTX cut of fossil fuel refining of which benzene is most important for aromatic manufacture. Benzene exposure has been linked to acute leukemia and non-Hodgkin's lymphoma. The environmental release of benzene must be reduced as mandated by the Chemical Manufacturing Rule issued by the U.S. Environmental Protection Agency.;Establishing the connectivity between the carbohydrates D-glucose, D-xylose and L-arabinose and aromatic molecules is the first step towards development of alternative starting materials for the manufacture of aromatic molecules by the chemical industry. Carbohydrates offer the advantage of being nontoxic, nonvolatile, and derived from renewable resources by the depolymerization of the biopolymers starch and cellulose.;The conversion of carbohydrates to the aromatics catechol and hydroquinone along with the polyhydroxybenzene pyrogallol have been established from the intermediates of the shikimate pathway for aromatic amino acid biosynthesis. An Escherechia coli construct has been developed for the conversion of D-glucose to the hydroaromatic myo-inositol in 20 g/L. Oxidation of the axial alcohol of myo-inositol by Gluconobacter oxydans ATCC 621 affords myo-2-inosose. Acid-catalyzed dehydration of myo-2-inosose affords 1,2,3,4-tetrahydroxybenzene in 66% yield which has been established as a starting material for aurantiogliocladin and coenzyme Q3. Attempts to increase the titer of myo- inositol by fed-batch fermentation or the direct conversion of D-glucose to myo-2-inosose in one microbial host will be discussed. 2-Deoxy-scyllo-inosose, which could be obtained from butirosin biosynthesis in Bacillus circulans, has been aromatized to hydroxyhydroquinone in 39% yield under acid-catalyzed dehydration conditions.;Triacetic acid lactone, obtained from an inadequate supply of NADPH during the biosynthesis of fatty acids or the polyketide 6-methyl salicylic acid, has been converted to phloroglucinol and resorcinol. Efforts towards the biosynthesis of triacetic acid lactone either by fatty acid biosynthesis or polyketide biosynthesis will be discussed. Resorcinol can be derived from phloroglucinol methyl ether in 80% yield by the development of a novel deoxygenation methodology for polyhydroxybenzenes. The general utility of the deoxygenation methodology has been established by the conversion of phloroglucinol to resorcinol in 82% yield, 1,2,3,4-tetrahydroxybenzene to pyrogallol in 44% yield and the conversion of hydroxyhydroquinone to hydroquinone in 53% yield. |
