白曲霉产中温酸性α-淀粉酶组成成分分析及酶学性质的研究

Analysis of the Compositions of Medium-temperature Acid α-Amylase from Aspergillum candidus and Its Enzymatic Properties

对高产白曲霉菌株产生中温酸性α-淀粉酶进行了酶学性质研究,试验表明该酶最适作用温度为60℃,最适作用pH为5.0,该酶在pH4.5～7.0范围内酶活较稳定,金属离子对此酶几乎没有激活作用,Hg+、Fe3+对酸性α-淀粉酶有明显的抑制作用。酸性α-淀粉酶的Vmax为311.53mg/(u·min),Km为2.18mg/(u·min)。该酶具有较好的耐热性和耐酸性,能在同一pH条件下进行淀粉的液化和糖化作用,具有较好的应用前景。

The enzymatic properties of medium-temperature acid α -amylase from Aspergillum candidus were studied. The experimental results were as follows： the optimum temperature was at 60 ℃,the best pH value was 5.0, the enzyme performed stably as pH value was between 4.5～7, metal irons could hardly activate the enzyme, and Hg＋ and Fe3＋ could evidently inhibit the enzyme. Kinetics analysis showed that its Vmax= 311.53 mg/u/min and its Km=2.18 mg/u/min.The enzyme had good acid tolerance and thermo-stability and it could achieve liquefaction and saccharification of the starch spontaneously under the same pH value. Accordingly, the enzyme had favorable application foreground.