【作者】 张云；

【导师】 刘东波；

【作者基本信息】 东北师范大学 ， 微生物学， 2008， 硕士

【摘要】 本文利用三点法和插片法对黑曲霉SB-02(Aspergillus Niger SB-02)菌株进行了菌落形态及菌株的观察:利用双层平板法和三点法研究了黑曲霉SB-02菌株对培养基中木聚糖的降解情况:通过摇床培养,初步测定了黑曲霉SB-02菌株所产木聚糖酶的活性大小。同时对黑曲霉固体发酵木聚糖酶的条件进行了优化,优化因子有:碳源,氮源,培养温度,培养时间,初始pH值,初始水分,接种量,浸提剂等。结果表明:以麸皮和玉米芯质量比7:3混合后作为碳源,以0.15%的硫酸铵为无机氮源,物料与水分的比为1:1;培养温度28-30℃;培养基起始pH值为4.8;接种量为4%(107个/ml),加入0.05%的吐温-20,发酵时间为72h,加入10倍培养基干重的自来水,于40℃摇床浸提1h,得到的木聚糖酶活为650.45IU/ml。将固体发酵得到的粗酶经过滤、离心、超滤、冻干,制得粗酶粉,研究了粗酶粉的组分和反应特性,结果表明:在所得到的粗酶粉中,含有多种降解酶组分,分别是木聚糖酶、纤维素酶,滤纸酶、淀粉酶;分别占总酶活的66.3%、17.1%、3.8%、12.7%;粗酶的最适反应温度为50℃,最适反应pH值为4.8,Fe3+对酶活具有较强的激活作用, Mg2+具有一定的抑制作用,其他金属离子无显著作用。经过DEAE A-25葡聚糖凝胶层析发现,黑曲霉木聚糖酶中含有X-Ⅰ,X-Ⅱ,X-Ⅲ三种木聚糖酶同工酶组分,X-Ⅰ为不吸附组分;X-Ⅰ,X-Ⅱ含量较少,X-Ⅲ含量较高。经PAGE,三种组分均呈单一条带。经纯化,木聚糖酶的比活力提高了2倍左右,酶活回收率为26.3%。更多还原

【Abstract】 The paper uses three-point method and the interpolation method to abserve the colony morphology , external hyphae and spores of the laboratory-preserved Aspergillus niger SB-02. It is studied the Aspergillus niger SB-02’s degradation of xylan on double-deck plate and determinated the activity of xylanase after 3 days liquid fermentation.The paper focus on optimization of the solid fermentation conditions for xylanase. Optimization factors are as follows: carbon, nitrogen, temperature, incubation time, the initial pH , the initial moisture, inoculation, extraction, etc. The results show that: the bran and corn-cob are mixed at ratio 7:3 as a mixtured carbon source; the best inorganic nitrogen source is ammonium sulfate(0.15%); the ratio of the materials and the water is 1:1 ; the appropriate culture temperature is 28-30℃; the initial pH is 4.8; the appropriate inoculation is 4% (107 / ml); the content of Tween-20 is 0.05%; the liquid fermentation time is 72 hours; 10 times the medium of water, extracted for 1 hour at 40℃; the activity of xylanase is up to 650.45 U/ml.The crude enzyme powder is made from extraction,filtration,centrifugation,ultrafiltration, freeze-dried of the solid-state fermentation. The results show that: the crude enzyme powder contains various degrading enzymes,such as xylanase, cellulase, filter enzyme, amylase; respectively,their activity is 66.3%, 17.1% and 3.8% , 12.7%; the optimum reaction temperature of the crude xylanase is 50℃and the optimum reaction PH value is 4.8; Fe3+ strongly actived the activity of the xylanase; Mg2+ has a certain inhinition ; the Other metal ions have no significant role.After dextran gel chromatography of DEAE A-25 ,we found that Aspergillus niger xylanase contains three isozyme: X-Ⅰ, X-Ⅱ, X-Ⅲ. X-Ⅲis not a adsorption component; the content of X-Ⅰ, X-Ⅱare fewer than X-Ⅲ. After PAGE ,three isozymes all showed a single band. After purification, Xylanase activity increases 2 times and enzyme recovery is 26.3%.更多还原