||该文对黑曲霉Uγ-2菊粉酶的产生过程进行了研究.结果表明:发酵初期产酶速率较快,pH下降速度快.在发酵进行到96~120h期间,出现产酶的迟缓期,此时发酵液的pH为4.38~4.22;以后菊粉酶活力明显上升.在192h菊粉酶活力达到最高值,发酵液pH降到最低点(3.54).在发酵进程中,发酵液可溶性蛋白出现2个高峰,与菊粉酶活力变化曲线比较,表明在72h出现的第一高峰主要是杂蛋白;在192h出现的第二高峰主要表现菊粉酶的产生.与生物量的变化曲线比较,尽管在发酵初期产酶速率较快,但菊粉酶在发酵液中大量积累出现在120h后(对数增长期的后期). 本研究通过采用聚丙烯酰胺凝胶电泳分析方法,研究了细胞外菊粉酶、细胞内菊粉酶和细胞壁菊粉酶酶组分的构成和动态变化.结果表明:三部分菊粉酶在酶组分构成上存在着显著的差异,并且细胞内无细胞外菊粉酶组分,因此可推测出细胞外菊粉酶的分泌方式为同转译分泌;细胞外菊粉酶各组分合成之后同时分泌出来.在不同发酵时期测定细胞外、细胞内和细胞壁菊粉酶活力研究酶活力变化趋势,结果表明,细胞外菊粉酶活力在发酵192h后达到最高值,细胞外菊粉酶的合成与细胞生长同步进行,属于延续合成型的酶.在发酵24~48h之间,细胞内菊粉酶活力下降较快,48~120h胞内酶活力降低缓慢,120h后细胞内菊粉酶活力变化不大.而细胞壁菊粉酶24h酶活力最高,24~48h酶活力急剧下降,48h以后酶活力基本保持不变. 研究了环境因素对菊粉酶合成和分泌的影响.结果表明,菊粉对细胞外菊粉酶的合成有一定的诱导性,菊粉降解产物果糖和葡萄糖对细胞外菊粉酶的合成无抑制作用,通过流加葡萄糖的方法可以提高酶活力20.91U.添加吐温80未提高细胞外菊粉酶的产量;在培养基中加入玻璃珠破坏菌丝球的形成降低了菊粉酶活力;加入脱壁酶促进酶产生,酶活力提高了30.72U.
||The process of inulinase yielding from Aspergillus niger Uy-2 was studied . The rate of inulinase yielding and that of pH declined were fast in the initial fermentation phrase.The production of extracellular inullnase is less than other time, when pH is between 4.38?.22. The maximum of extracellular inulinase acticity(EIA) and the minimum pH showed at the same time(192 h). There were two soluble protein(SP) peaks occurred in the fermentation course. The fist one was given at 72 h, which was compose of the impure protein,and the other showed the synchronism and the increase of EIA. Analysis of the changes of biomass(BM)showed that the optimal extracellular inulinase yielding phase was the period of 120?92 h.(anaphase of the logarithmic growth phase and the whole stationary phase). The forming and the dynamic changing of inulinases, which were extracted from supernant cell-wall and introcell, were studied by polyacrylmidegel electrophoresis(PAGE). Three sections of inulinase presented significant difference, and there were no extracellular inulinase compositions in cell. The secretory mode of extracellular inulinase was associated with translation. The maximum of EIA was showed at 192 h, inulinase synthesis accompanied the cell growth, the enzyme was continued a period time when the groth of cell was stationary phase. The intracellular inulinase activity(llA) and the cell-wall inulinase activity(CIA) were decreased quickly at 24?8 h, the llA decreased and the CIA hardly varied after 48 h. Evironmental agent effected inulinase synthesis and secretion were studied. lnulin was one inducer to the synthesis of extracellular inulinase. The degradation production of glucose and fructose had no inhibition on extracellular inulinase synthesis. The EIA was raised 20.9W by adding glucose during fermentation period. The yielding of inulinase wasn\''t effected by Tween 80, The EIA was decreased by the forming of mycellum pellet destructed by adding the glass ball, wheras the EIA was increased 30.72U by adding lywallzyme(120 h).