真菌木聚糖酶产生菌的筛选及酶学性质研究

本实验通过土壤稀释涂布法，经过初筛、复筛，筛选出了两株酶活力较高真菌菌株C4 和G1，在此基础上对它们生长的最佳碳源选择、酶学性质进行了研究。结果表明：菌株C4 产酶的最佳碳源为玉米芯－麸皮，培养24h 就可以达到产酶高峰，其酶活力达6582.29U/ml。此酶反应最适温度为40℃，在50℃以下比较稳定，最适反应pH 值为5.0，并且pH 稳定性比较好；菌株G1 产酶的最佳碳源为玉米芯，培养96h 就可以达到产酶高峰，其酶活力到达6301.04U/ml。此酶反应的最适温度是40℃，在40℃以下比较稳定，最适反应pH 值为5.0，但pH 值稳定性不如菌株C4。

Screening of Tow Xylanase-producing Fungus Strains and Study on Enzymological Properties of Produced Xylanases

Two strains of fungi (C4 and G1) producing high activity xylanase were isolated by soil dilution coating method and through primary and repeated screening. Furthermore, the optimum carbon source for their growth and enzymological properties of xylanases produced by them were studied. The results showed that the best carbon source for strain C4 producing xylanase is the mixture of corncob and bran. The xylanse activity produced by strain G4 reaches the peak after cultivation for 24h, 6582. 29 U/ml. The optimum reaction temperature of the xylanse is 40 ℃ and it is relatively stable below 50 ℃. Its optimum reaction pH is 5.0 and it shows good pH stability; The best carbon source for strain G1 producing xylanase is corncob. The xylanase activity produced by strain G1 reaches the peak after 96 hours of cultivation, 6301.04 U/ml. The optimum reaction temperature of xylanase produced by strain G1 is 40 ℃ and it is stable below 40 ℃. The optimum reaction pH is 5.0, but its stability is less than that of xylanase produced by strain G4.