FERMENTATION OF GLYCEROL TO 1,3-PROPANEDIOL - USE OF COSUBSTRATES

Three fermentable substances, glucose, 1,2-ethanediol and 1,2-propaned iol were checked as cosubstrates for the fermentation of glycerol by C lostridium butyricum and Citrobacter freundii with the aim of achievin g a complete conversion of glycerol to 1,3-propanediol. Glucose was fe rmented by C. butyricum mainly to acetate, CO2 and reducing equivalent s in the presence of glycerol and contributed markedly to the 1,3-prop anediol yield. However, because of relatively slow growth on glucose, complete conversion was not achieved. If the two glycols were used as cosubstrates for glycerol fermentaton, the 1,3-propanediol yield did n ot increase but dimished considerably, as they were converted to more reduced products, i.e. alcohols instead of acids. From 1,2-propanediol 2-propanol was formed in addition to 1-propanol. The ratio of the pro panols was dependent on the culture conditions.