一株霉菌产木聚糖酶固态发酵培养基的优化及酶学性质研究

Optimization of Solid Fermentation Culture Medium for a Fungal Xylanase-producing Strain and Study on Its Zymology Properties

对一株霉菌B45固态发酵产木聚糖酶的培养基组分进行优化,通过单因素实验观察了不同碳源、氮源、无机盐、水料比4种因素对产木聚糖酶的影响,确定了4种最佳的单因素成分。在单因素的基础上,再通过正交实验确定了所试因素的最佳组合,并对其粗酶的酶学性质进行了研究。结果表明,在培养基组分为玉米芯与麸皮的比例=7∶3,硫酸铵为1.5%,KH2PO4为0.8%,水料比为2.1∶1时,得到的酶活力最高,产酶量可达1 079.93 U/g。其粗酶液的最适反应温度为60℃,最适反应pH为5,在pH5～pH6的范围内酶活性较稳定。但粗酶液的热稳定较差,在40℃条件下酶活力开始下降,当温度升至70℃时酶活力损失85%以上。

The compositions of solid fermentation culture medium for the fungal xylanase-producing B45 strain were optimized. The best four single-factor components were determined according to the effects of different carbon and nitrogen sources, inorganic salts, water-material ratio on xylanase-producing observed in the single-factor test, and on the base of this test, the best combination of tested factors were confirmed through the orthogonal experiment and its zymology properties was also studied. The results showed that the best compositions of the culture medium are as follow： corncob and bran ratio 7 ： 3, ammonium sulfate 1.5 %, KH2 PO4 0.8 %, water materials ratio 2.1： 1. In this condition, enzyme activity is the highest and its yields reaed 1 079.93 U/g. The optimum reaction temperature of crude enzyme solution is 60 ℃; the optimal pH is 5 and the enzyme activity maintains its stability at pH 5 to 6 range. But the thermal stability of crude enzyme solution show poor, enzyme activity started to decline at 40 ℃ and will lose its 85 % when temperature rises to 70 ℃.