Abstract
Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of l-tryptophan produced with a genetically modified strain of Escherichia coli (CCTCC M 2024517) as a nutritional additive in feed and water for drinking for all animal species and categories. The l-tryptophan produced by fermentation with E. coli CCTCC M 2024517 did not give rise to any safety concern regarding the genetic modifications of the production strain. No viable cells nor DNA of the production strain was detected in the final product. The use of l-tryptophan produced with E. coli CCTCC M 2024517 in feed is safe for the target species when supplemented in appropriate amounts to the diet according to their nutritional needs. The FEEDAP Panel had concerns on the use of l-tryptophan in water for drinking. The use of l-tryptophan produced by fermentation with E. coli CCTCC M 2024517 in animal nutrition was considered safe for the consumers of products from animals receiving the additive and for the environment. The FEEDAP Panel could not conclude on the potential of the additive to be an irritant to skin and/or eyes and to be a potential skin sensitiser. The additive was regarded as an effective source of the amino acid l-tryptophan for all non-ruminant species. To be as efficacious in ruminants as in non-ruminants, it should be protected from ruminal degradation.