Enhancing the microbial conversion of glycerol to 1,3-propanediol using metabolic engineering

1,3-propanediol (PDO) is the starting point of a new generation polymer with superior properties which is used in the textile and carpet industry. This product is mainly produced chemically, but high pressure, high temperature and expensive catalysts are required and toxic intermediates are released. Therefore, the biological production route has been studied intensively. DuPont and Genencor International, Inc. have modified E. coli genetically so that this organism could produce PDO from glucose. However, due to the tremendous growth of the biofuel industry, a glycerol surplus has been created, so more and more researchers started to investigate the natural producing strains for the production of PDO from glycerol. Several metabolic engineering techniques have been used to enhance the production of PDO. This review gives an overview of the different strategies to increase the final titer, yield and productivity of 1,3-propanediol in non-natural and natural producing strains