Biotechnological conversion of glycerol to 2-amino-1,3-propanediol (serinol) in recombinant Escherichia coli.

Microbial conversion is an important technology for the refinement of renewable resources. Here, we describe the biotechnological conversion of glycerol to 2-amino-1,3-propanediol (serinol), a relevant intermediate in several chemical syntheses processes. Either the dihydroxyacetone phosphate aminotransferase/dihydrorhizobitoxine synthase (RtxA) of Bradyrhizobium elkanii USD94 or only the N-terminal domain (RtxA513) comprising the first reaction, respectively, was expressed in recombinant Escherichia coli. Serinol contents of up to 3.3 g/l were achieved in batch cultures. We could further clarify that glutamic acid is the preferred cosubstrate for the transamination of dihydroxyacetone phosphate to serinolphosphate, which is the essential step in serinol synthesis. An in vivo detoxification of serinol employing wax ester synthase/acyl-CoA:diacyl-glycerol acyl transferase from Acinetobacter baylyi ADP1 was not accomplished. This study paves the way for biotechnological production of serinol from glycerol derived from the biodiesel industry.