Improved 1,3-propanediol production by Escherichia coli from glycerol due to Co-expression of glycerol dehydratase reactivation factors and succinate addition

Escherichia coli was engineered to produce 1,3-propanediol (1,3-PDO) from glycerol, an inexpensive carbon source. This was done by introducing a synthetic pathway consisting of glycerol dehydratase, glycerol dehydratase reactivation factor, and 1,3-propanediol oxidoreductase isoenzyme. The JM-30BY15AB harboring pQE30/ dha B123, yqh D and pQE15A/ gdr A, gdr B produced 1,3-PDO (7.2 g/L) from glycerol, at a level higher than that produced by JM-30BY harboring pQE30/ dha B123, yqh D (4.1 g/L). When 10mM succinate was added to the medium, the titer of 1,3-PDO and the glycerol consumption increased to 9.9 and 23.84 g/L, respectively. In addition, the ratio of NADH to NAD + increased by 43%. The titer of 1,3-PDO and glycerol consumption were 145.6 and 86.6% higher, respectively, than those from the control which harbors one vector system without gdr AB and did not include succinate addition. Under fed-batch fermentation conditions, the titer of 1,3-PDO and its conversion yield from glycerol were 13.11 g/L and 0.49 g/g, respectively. This dual-vector system may be a useful approach for the co-expression of recombinant proteins. Further, succinate addition is a promising route for the biotechnological production of NADH-dependent microbial metabolites.