Preparation of endo-1,4-beta-xylanase (EC 3.2.1.8)

In the current applications, authorisations are sought under Article 4 for a preparation of endo-1,4-beta-xylanase (EC 3.2.1.8) for piglets, other minor growing porcine species, all avian species, ornamental, exotic and game birds, under the category/functional group 4 (a) "zootechnical additives"/"digestibility enhancers" according to Annex I of Regulation (EC) No 1831/2003.
According to the Applicant, the active substance of the feed additive is endo-1,4-beta-xylanase, produced by fermentation of the genetically modified yeast Komagaetella phaffii CGMCC 7.371. The activity of endo-1,4-beta-xylanase is expressed in xylanase units (U), where one unit is the amount of enzyme required to release one micromole of reducing sugar equivalents from arabinoxylan per minute at 37 °C and pH 6.5.
The feed additive is intended to be marketed as powder (VTR-xylanase powder) and liquid (VTR-xylanase liquid) formulations, having a guaranteed minimum endo-1,4-beta-xylanase activities of 100000 and 30000 U / g respectively and it is intended to be incorporated directly into complete compound feed or through premixtures to obtain a minimum xylanase activity of 1000 or 2000 U / kg compound feed depending on the target species.
For the determination of endo-1,4-beta-xylanase (xylanase) in the feed additive, premixtures and compound feed the Applicant submitted a single-laboratory validated and further verified colorimetric method, based on the quantification of water soluble dyed fragments produced by the action of xylanase on a commercially available (Xylazyme AX®, Megazyme) azurine cross-linked wheat arabinoxylan substrate.
Based on the experimental evidences and on the acceptable performance characteristics provided by the Applicant, the EURL recommends for official control the colorimetric (Megazyme) method for the determination of 1,4-beta-xylanase in the feed additive, premixtures and compound feed.
Further testing or validation of the methods to be performed through the consortium of National Reference Laboratories as specified by Article 10 (Commission Regulation (EC) No 378/2005, as last amended by Regulation (EU) 2015/1761) is not considered necessary.