Synthesis of 1, 3- Propanediol from Sorghum

Abstract

1, 3-Propanediol (PDO) is the commonest diol used in polyester synthesis, polyurethanes and cyclic compounds. Starch was prepared from white sorghum. Dual enzyme technique was used to convert starch to sugar. Then glycerol was formed by fermentation of the sugar by yeast after 72 h. Mixed culture of Escherichia coli and Klebsiella specie was used to inoculate the glycerol obtained for final conversion to 1, 3-propanediol. The mixture was left for 72 h to ensure complete conversion. The reaction temperature for fermentation was 37^oC. The expression of Klebsiella sp-diol dehydratase in E-coli catalyzed the conversion of glycerol to 1, 3-propanediol. The sample was then re-filtered, distilled and condensed to obtain the pure, bio-PDO which is colourless and odourless. Biologically produced 1, 3-propanediol was characterized and the result is as follows: specific gravity = 0.9992, purity 99.92%, boiling point 121-124^oC. The PDO synthesized was found to be of comparable purity to chemically produced PDO.