The present inventions relates to a modified GH10 xylanase enzyme or a fragment thereof having xylanase activity wherein said modified GH10 xylanase or fragment thereof has increased thermostability compared with a parent GH10 xylanase enzyme, the parent GH10 xylanase having been modified at, at least, two of the following positions 7, 33, 79, 217 and 298, wherein the numbering is based on the amino acid numbering of FveXyn4 (SEQ ID No. 1). In particular, the modified xylanase enzyme according to the present invention has the following modifications:N7D；T33V；K79Y, V, F, I, L or M (preferably K79Y, F or V, more preferably Y)；A217Q, E, P, D or M (preferably A217Q, E or P, more preferably Q)； andT298Y, F or W (preferably Y or F, more preferably Y).
