Microbial conversion of glycerol to 1,3-propanediol

Glycerol produced by cleavage of natural fats can microbially be converted to 1,3-propanediol (PD) by Citrobacter, Klebsiella and Clostridia strains. The fermentation by C. butyricum, product recovery and purification has been investigated in detail up to the 2 m3 scale. Estimation of product costs for a 10,000 t/a plant indicates that the microbial process is obviously more attractive than the chemical route. Presently, 1,3-propanediol has only a low market volume; however, its use for special polycondensates, in particular polyesters, could reduce glycerol surpluses and make plastics a easily biodegradable part of natural cycles.