作　　者： ; ; ; ; ;

机构地区： 湛江海洋大学水产学院

出　　处： 《热带海洋学报》 2005年第6期6-12,共7页

摘　　要： 将地衣芽孢杆菌Bacillus licheniformis的胞外产物置于不同的pH、温度和金属离子条件下,分别测定其蛋白酶、淀粉酶、脂肪酶活性的变化。结果表明,当pH为7.5—8.5时胞外产物表现出较高的蛋白酶和淀粉酶活性,胞外产物消化脂肪的最适pH为9.0—10.0。胞外产物水解淀粉、脂肪和蛋白质最适温度分别为60—80、40—60和50—70℃,60℃时蛋白酶活力最大。试验测定了8种金属离子对胞外产物活性的影响,发现Mg2+、Zn2+Cu2+可抑制其水解蛋白质,而Ca2+、Fe3+、Mn2+和Ba2+却无此影响;在胞外产物消化脂肪底物时Co2+、Fe3+、Mn2+和Ba2+均能抑制其活力,而Mg2+、Zn2+能使其消化活力升高,与前者相比,金属离子对淀粉水解的影响相对较小,仅Cu2+有一定的抑制作用,其它离子对其均无明显的影响。还研究了不同胞外产物浓度与生物学活性的相关性,发现当反应体系中胞外产物浓度升高时水解蛋白质的活力会相应降低,但对脂肪的消化活力则与胞外产物的浓度呈正相关。反应体系中胞外产物的浓度在0—132.4μg.ml-1时其水解淀粉的活力随浓度的升高而升高,浓度为191.0μg.ml-1时活力最大,浓度大于191.0μg.ml-1时活力不再变化,稳定在一个较高的水平。 The effects on digestive activities of under different conditions of pH, temperature extracellular product of Bacillus lichenformis and metal ions were studied. After incubated in different conditions for 30-60 minutes, the extracellular enzymatic activities of Bacillus lichenformis were measured. The results showed that the optimum pH for the extracellular protease and amylase was 7. 5-8. 5 and their activities were high within this pH range, while the enzymatic activity of extracellular lipase was the highest at pH of 9.0-10.0 and the lowest at pH of 7. 5-8.5. Influence of temperature on different extracellular enzyme was dissimilar, the optimum temperature for the extracellular protease was 50-70℃ and it reached its maximum enzymatic activity at 60℃, and the optimum temperature for the extracellular amylase and lipase were 60-80℃ and 40-60℃, respectively. Different metal ions had distinct influence on extracellular enzymatic activities of Bacillus lichenformis. Mg^2＋ , Zn^2＋ and Cu^2＋ ions inhibited the enzymatic activity of extracellular protease, but Ca^2＋, Fe^3＋ , Mn^2＋ and Ba^2＋ ions had little effect on protease. The extracellular lipase was activated by Mg^2＋ and Zn^2＋ ions, but inhibited by Ba^2＋ , Fe^2＋ , Mn^2＋ and Co^2＋ ions. The extracellular amylase was not inhibited by all of the metal ions except Cu^2＋. The enzymatic activities of extracellular protease decreased with the increase of the extracellular enzyme concentration, contrary to the situation of extracellular lipase. However, the concentration of extracellular enzyme had different effects on eXtracellular amylase. The enzymatic activity was remarkably enhanced at the extracellular enzyme concentration of 0-132.4μg·ml^-1 , and reached its maximum at the optimum concentration of 191.0μg·ml^-1. The enzymatic activity of extracellular amylase stayed on a balanced level and changed little when the concentration exceeded 191.0μg·ml^-1.

关 键 词： 地衣芽孢杆菌 胞外产物 温度 金属离子 活性

领　　域： [生物学] [生物学]