Abstract:

Xylanase was separated and purified from a culture filtrate of Trichoderma Koningii through ammonium sulfate precipitation.Sephadex G-25 and Sephadex G-100 column chromatography.The purified xylanase was then proved by SDS.PAGE to be a single composition with a relative molecular mass of 55 208.Good thermostability of xylanase with an optimal activity at 65 ℃ and pH 6.0 was also revealed.The results show that more than 83% or 85% of the relative activity of xylanase can be remained when respectively stored at 30~60 ℃ for 2 h or in the pH range of 3.0 ~10.0. Moreover,Ba²⁺,Pb²⁺,Fe²⁺,Fe³⁺,,Al³⁺ and 12mmol/L Cu²⁺ are strong inhibitors to xyla-nase.while Ca²⁺ ,Zn²⁺ and 4 mmol/L Cu²⁺ are stimulators．The Michaelis．Menten constant of xylanases in the enzymatic hydrolysis of birchwood xylan iS 5.37 g/L.and the maximal reaction velocity iS 0.94μmol/min．

Key words: xylanase, Trichoderma Koningii, separation, purification, enzyme activity