PL73 Escherichia coli (LM) is a genetically modified strain of E. coli K-12 named strain 19E. Strain 19E has been constructed from a specific mutant strain of E. coli K-12, strain E. coli- K-12S B-7, in several steps. The strategy of construction was based, among others, on chromosomal insertion for the genes introduced. Except for one modification, the only genes transferred in the final strain 19E correspond to the over-expression of existing metabolic enzymes for the synthesis/production of amino acids.

The purpose of the genetic modifications is to obtain a high production rate of L-lysine.

Southern blots have shown that none of the antibiotic resistance genes used for intermediate constructions are present in the genome of strain 19E. Further hybridizations have shown the stability of the copies integrated in the genome even after 15 to 20 generations.

Source: EFSA document, Application submitted under regulation (EC) No 1829/2003: EFSA-Q-2008-669b, Part II - Summary of EFSA-GMO-FR-2008-61