中国新分离碱性耐热芽孢杆菌的木聚糖酶产酶特征

目的：检测由中国新分离碱性耐热芽孢杆菌1]产生的粗木聚糖酶的酶活。方法：通过DNS法测定粗木聚糖酶的酶活。结果：实验表明,以橡树木聚糖为底物培养的新分离菌株在30-50℃处理2h酶活不丧失。其中,XJU-1菌株在60、70和80℃时粗酶酶活分别丧失是最初酶活的1.54%、19.09%和72.59%;而XJU-80的粗酶酶活分别是3.59%、26.43%和72.59%。两个菌株产生的粗木聚糖酶的最适pH是7.5-8.0。将该粗酶在pH 7.0-9.0（50℃）处理24h后,酶活几乎均降低最初酶活的18%。结论：由XJU-1和XJU-80产生的木聚糖酶是生化领域有用的嗜碱耐热酶。

Xylanase Production and Properties by Newly Isolated from Thermostable Alkaliphilic Chinese Bacillus Strains

Objective: To detect the activity of xylanases produced by the newly isolated and thermostable alkaliphilic Chinese Bacillus halodurans XJU- 1 and Bacillus halodurans XJU- 801] . Mehtods: By DNS method, the data of activity of the crude xylanases was obtained. Results:Studies on the xylanase characterization from liquid cultures grown on oat spelts xylan revealed that the enzyme retained 100% of activity for 2 hours at temperature ranging from 30 to 50℃,while for B. halodurans XJU- 1 at 60,70 and 80℃,1.54%, 19.09%, and72.59% of the original activities were lost, respectively; and for B. halodurans XJU- 80, 3.59%, 26.43% and 72.59%, respectively. The optimum pH of all the two enzymes was found to be pH7.5-8.0. After incubation of crude enzyme solution for 24 hours at 50℃ andat pH 7.0 to 9.0, a decrease of about 18% of their original activity was observed. Conclusion: The xylanases produced by the two isolates were alkaliphilic and thermostable enzymes which would be useful in biotechnological fields. And the data of the activity of the crude xylanase would be necessary for cloning the xynlanase genes2] and purifying the enzyme proteins from the newlyislolated species of B. halodirans XJU- 1 and B. halodurans XJU- 80.