Optimization of extracellular 5-aminolevulinic acid production from Escherichia coli transformed with ALA synthase gene of Bradyrhizobium japonicum

Extracellular accumulation of 5-aminolevulinic acid (ALA) by an E. coli ove rexpressing ALA synthase (ALAS) was achieved by inserting a hemA gene from Bradyrhizobium japonicum and expressed under the control of T7 promoter. At pH 7.0 extracellular ALA reached up to 15 mM in a jar fermenter with an ad dition of glycine (30 mM) and succinate (90 mM) in the medium. ALA accumula tion was increased to 20 mM by adding levulinic acid (30 mM) to the culture s.