Safety and efficacy of l‐tryptophan produced by fermentation with Escherichia coli KCCM 80135 for all animal species

nutritional additive, amino acids,L-tryptophan, safety, efficacy,Escherichia coliKCCM 80135
First published in the EFSA Journal
7 May 2019
2 April 2019
Scientific Opinion


Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on l‐tryptophan produced by fermentation using Escherichia coli KCCM 80135 when used as a nutritional additive in feed and water for drinking for all animal species. The production strain and its recombinant DNA were not detected in the additive. l‐Tryptophan produced by fermentation with E. coli KCCM 80135 does not raise any safety concern with regard to the genetic modification of the production strain. The use of l‐tryptophan produced using E. coli KCCM 80135 in supplementing feed to compensate for tryptophan deficiency in feedingstuffs is safe for non‐ruminant target species. Using unprotected forms of tryptophan in ruminants can be a risk. The use of l‐tryptophan produced by fermentation using E. coli KCCM 80135 in animal nutrition presents no safety concerns to consumers of animal products. l‐Tryptophan produced by E. coli KCCM 80135 is not toxic by inhalation. The additive is not an irritant to skin and eyes, and it is not a skin sensitiser. The additive under assessment is considered safe for the environment. It is regarded as an effective source of the amino acid l‐tryptophan for all non‐ruminant species. If the additive l‐tryptophan is intended for use in ruminants, it should be protected from ruminal degradation.

Panel members at the time of adoption

Giovanna Azimonti, Vasileios Bampidis, Maria de Lourdes Bastos, Henrik Christensen, Birgit Dusemund, Maryline Kouba, Mojca Kos Durjava, Marta López‐Alonso, Secundino López Puente, Francesca Marcon, Baltasar Mayo, Alena Pechová, Mariana Petkova, Fernando Ramos, Yolanda Sanz, Roberto Edoardo Villa and Ruud Woutersen.
Panel on Additives and Products or Substances used in Animal Feed
feedap [at]
EFSA Journal 2019;17(5):5694
Question Number
On request from
European Commission
Relevant information or parts of this scientific output have been blackened in accordance with the European Commission decision on the confidentiality requests formulated by the applicant. The full output has been shared with the European Commission, EU Member States and the applicant.