耐热子囊菌产木聚糖酶及酶学性质的研究

Study on Production and Property of Xylanase by Thermoascus aurantiacus Using Solid State Fermentation

对 1株耐热子囊菌 (Thermoascusaurantiacus)固态发酵产木聚糖酶的工艺条件及酶学性质进行了研究。确立了适宜的产酶基质为 :麸皮 3 0 %、玉米芯 3 5 %、玉米皮 3 5 %、(NH4 ) 2 SO4 2 %、尿素 0 5 %、KH2 PO4 0 5 %、MgSO4 ·7H2 O 0 2 %、初始含水量 65～ 70 %。 45℃培养 5d ,木聚糖酶活力最高可达 1 0 3 2 1IU/g(干曲 )。该木聚糖酶最适反应温度为 70℃ ,最适pH4 8;在 pH3 0～ 7 0 ,温度低于 65℃时稳定性能较好。可被Fe2 +、Mg2 +、Zn2 +激活 ,而被Co2 +、Fe3+、Mn2 +抑制。

Xylanase production by Thermoascus aurantiacus was studied under solid state fermentation process. The culture substrate was optimized as follows:wheat bran 30%, corncob 35%, corn husk 35%, (NH_4)_2SO_4 2%, carbamide 0.5%. The initial moisture content 65%～70%. Xylanase activity reached 10 321?IU/g koji after 5days at 45℃. Study on the enzyme properties showed that the optimal pH value and temperature were 4.8 and 70°C, respectively. The enzyme was stable under 65℃,pH 3.0～7.0. Fe 2+,Mg 2+,Zn 2+ take various stimulus roles to xylanase activity, whereas Co 2+,Fe 3+, Mn 2+ inhibit xylanase activity. The enzyme has been widely applied in feeding, food, paper pulp, textile industries and the bioconversion of hemicelluloses.