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


Panel on Additives and Products or Substances used in Animal Feed
EFSA Journal
EFSA Journal 2016;14(1):4343 [13 pp.].
Panel Members
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.
The Panel wishes to thank the members of the Working Group on Amino Acids including Lucio Costa, Noël Dierick and Lubomir Leng and the members of the Working Group on Genetically Modified Microorganisms, including Boet Glandorf, Lieve Herman and Sirpa Kärenlampi, for the preparatory work on this scientific output. 
Opinion of the Scientific Committee/Scientific Panel
On request from
European Commission
Question Number
1 December 2015
Published in the EFSA Journal
5 January 2016
European Food Safety Authority (EFSA), Parma, Italy

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.

nutritional additive, amino acids and their salts and analogues, L-tryptophan, safety, efficacy, genetically modified microorganisms
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