Safety of L-tryptophan produced by fermentation using Escherichia coli CGMCC 3667, for all animal species based on a dossier submitted by GBT Europe GmbH

nutritional additive, amino acids and their salts and analogues, L-tryptophan, safety, efficacy, genetically modified microorganisms
First published in the EFSA Journal
5 January 2016
1 December 2015
Scientific Opinion

L-Tryptophan, technically pure, is a feed additive produced by fermentation using a genetically modified strain of Escherichia coli (E. coli). The Panel on Additives and Products or Substances used in Animal Feed (FEEDAP Panel) of the European Food Safety Authority (EFSA), issued an opinion on the safety and efficacy of the product, in which it could not conclude on the safety of this additive for target animals, consumer, user and the environment, due to the insufficient characterisation of the genetic modification. The European Commission asked EFSA to deliver an opinion on the safety of L-Tryptophan, technically pure, as nutritional additive for all animal species based on additional data submitted by the applicant. The new information provided on the genetic modification, including the presence/absence of an antibiotic resistance gene in the production strain, is contradictory. Consequently, the FEEDAP Panel cannot conclude on the safety of the L-Tryptophan produced using E. coli CGMCC 3667 for target animals, consumers, users and the environment. The FEEDAP Panel reiterates its concern on the use of unprotected tryptophan to ruminants and on the safety of the amino acid L-Tryptophan for target species when administered simultaneously via water for drinking. As the estimated maximum exposure to endotoxins by inhalation is below the provisional occupational exposure limit, no risk from the exposure to endotoxins for people handling the additive is expected.

Panel members at the time of adoption
Gabriele Aquilina, Vasileios Bampidis, Maria de Lourdes Bastos, Georges Bories, Andrew Chesson, Pier Sandro Cocconcelli, Gerhard Flachowsky, Jürgen Gropp, Boris Kolar, Maryline Kouba, Secundino Lopez Puente, Marta Lopez-Alonso, Alberto Mantovani, Baltasar Mayo, Fernando Ramos, Guido Rychen, Maria Saarela, Roberto Edoardo Villa, Robert John Wallace and Pieter Wester.
Panel on Additives and Products or Substances used in Animal Feed
EFSA Journal 2016;14(1):4343
Question Number
On request from
European Commission