Safety evaluation of the food enzyme endo‐1,4‐β‐xylanase from Bacillus subtilis (strain XAS)

food enzyme, xylanase, endo-1, 4-b-xylanase, EC, 4-b-D-xylan xylanohydrolase, Bacillus subtilis, genetically modified microorganism
First published in the EFSA Journal
11 January 2019
4 December 2018
Scientific Opinion


The food enzyme is an endo‐1,4‐β‐xylanase (4‐β‐d‐xylan xylanohydrolase; EC produced with the genetically modified Bacillus subtilis strain XAS. Antibiotic resistance genes are present in the production organism on a self‐replicative vector. The endo‐1,4‐β‐xylanase is intended to be used in baking processes. Based on the maximum use levels, dietary exposure to the food enzyme–total organic solids (TOS) was estimated to be up to 0.014 mg TOS/kg body weight (bw) per day in European populations. Genotoxicity tests did not raise a safety concern. The systemic toxicity was assessed by means of a repeated dose 90‐day oral toxicity study in rats. The Panel identified a no‐observed‐adverse‐effect level (NOAEL) of 55 mg TOS/kg bw per day that, compared with the estimated dietary exposure, results in a sufficiently high margin of exposure (MOE) (of at least 3,600). 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 to occur is considered to be low. Since the absence of viable cells in the food enzyme has not been adequately demonstrated, the Panel cannot conclude on the risks associated with the possible spread of a genetically modified bacterial strain carrying antimicrobial resistance determinants.

Panel members at the time of adoption

Jose Manuel Barat Baviera, Claudia Bolognesi, Beat Johannes Brüschweiler, Andrew Chesson, Pier Sandro Cocconcelli, Riccardo Crebelli, David Michael Gott, Konrad Grob, Evgenia Lampi, Alicja Mortensen, Gilles Riviere, Vittorio Silano, Inger‐Lise Steffensen, Christina Tlustos, Henk Van Loveren, Laurence Vernis and Holger Zorn.
Panel on Food Additives and Flavourings
fip [at]
EFSA Journal 2019;17(1):5550
Question Number
On request from
European Commission