Safety evaluation of the food enzyme xylose isomerase from the genetically modified Streptomyces rubiginosus strain DP‐Pzn37

food enzyme, xylose isomerase, glucose isomerase, D‐xylose aldose‐ketose‐isomerase, EC, Streptomyces rubiginosus
First published in the EFSA Journal
20. Januar 2020
12. Dezember 2019
Scientific Opinion

Note: The full opinion will be published in accordance with Article 12 of Regulation (EC) No 1331/2008 once the decision on confidentiality will be received from the European Commission.


The food enzyme is a d‐xylose aldose‐ketose‐isomerase (EC produced with the genetically modified Streptomyces rubiginosus strain DP‐Pzn37 by Danisco US Inc. Although the production strain contains antibiotic resistance genes, the food enzyme was shown to be free from viable cells of the production organism and its DNA. The food enzyme is intended to be used in an immobilised form for the isomerisation of glucose for the production of high fructose syrups. Residual amounts of total organic solids (TOS) are eliminated by the use of an immobilised food enzyme and further removed by the purification steps applied during the production of high fructose syrups using the immobilised enzyme; consequently, dietary exposure was not calculated. Genotoxicity tests did not raise safety concerns. The systemic toxicity was assessed by a repeated dose 90‐day oral toxicity study in rats. The Panel identified a no observed adverse effect level of 85.2 mg TOS/kg body weight (bw) per day, the highest dose tested. Similarity of the amino acid sequence to those of known allergens was searched and no match was found. The Panel considered that, under the intended conditions of use, the risk of allergic sensitisation and elicitation reactions by dietary exposure cannot be excluded, but the likelihood is considered to be low. Based on the data provided, the immobilisation process and the removal of total organic solids during the production of high fructose syrups, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

Panel members at the time of adoption

José Manuel Barat Baviera, Claudia Bolognesi, Andrew Chesson, Pier Sandro Cocconcelli, Riccardo Crebelli, David Michael Gott, Konrad Grob, Evgenia Lampi, Alicja Mortensen, Gilles Rivière, Vittorio Silano, Inger‐Lise Steffensen, Christina Tlustos, Henk Van Loveren, Laurence Vernis and Holger Zorn.
Panel on Food Contact Materials, Enzymes and Processing Aids
fip [at]
EFSA Journal 2020;18(1):5978
Question Number
On request from
European Commission