The lack of a route to precursor 1,2,4-butanetriol that is amenable to large-scale synthesis has impeded substitution of 1,2,4-butanetriol trinitrate for nitroglycerin. To identify an alternative to the current commercial synthesis of racemic D,L-1,2,4-butanetriol involving NaBH4 reduction of esterified D,L-malic acid, microbial syntheses of D- and L-1,2,4-butanetriol have been established. These microbial syntheses rely on the creation of biosynthetic pathways that do not exist in nature. Oxidation of D-xylose by Pseudomonas fragi provides D-xylonic acid in 70% yield. Escherichia coli DH5α/pWN6.186A then catalyzes the conversion of D-xylonic acid into D-1,2,4-butanetriol in 25% yield. P. fragi is also used to oxidize L-arabinose to a mixture of L-arabino-1,4-lactone and L-arabinonic acid in 54% overall yield. After hydrolysis of the lactone, L-arabinonic acid is converted to L-1,2,4-butanetriol in 35% yield using E. coli BL21(DE3)/pWN6.222A. As a catalytic route to 1,2,4-butanetriol, microbial synthesis avoids the high H2 pressures and elevated temperatures required by catalytic hydrogenation of malic acid.
ASJC Scopus subject areas
- Colloid and Surface Chemistry