枯草芽孢杆菌2-3-2的抗线虫作用和产酶条件与酶特性

Effect of nematode resistance and enzyme production condition and enzyme characteristics of Bacillus subtilis 2-3-2

为了研究枯草芽孢杆菌2-3-2抗线虫作用与几丁质酶活的关系,对几丁质酶的产酶条件进行优化并探讨酶的特性,通过盆栽试验测定了抗线虫效果,用DNS定糖法测定了几丁质酶活力.实验结果表明:枯草芽孢杆菌2-3-2对南方根结线虫防治效果显著,其抗线虫作用与几丁质酶活性呈正相关.几丁质酶产酶培养基组成为(g/L):胶体几丁质65,酵母膏1,葡萄糖5,KH2PO40.7,K2HPO40.5,MgSO4·7H2O 0.5,FeSO40.01,NaCl 0.5,微量盐1mL/L;起始pH 7.0,温度为30℃、培养时间为72h.与优化前相比,酶活性提高了1.59倍,达到35.17×10-10 mol/s.枯草芽孢杆菌2-3-2几丁质酶最适反应温度为40℃,最适pH为7.0;温度高于50℃及碱性条件下酶活力下降.

In order to study the relationship between nematode resistance effect of Bacillus subtilis 2-3-2 and chitinase activity, and to optimize chitinase producing condition and discuss characteristics of chitinase , pot incubation test was used to determine nematode resistance effect and the DNS method was used to determine chitinase activity. The experiment results indicated that Bacillus subtilis 2-3-2 could control Meloidogyne incognita efficiently, and the capacity of nematode resistance is related to chitinase activity. The ingredient of enzyme producing medium is as follow（g/L）： colloidalchitin 65, yeast extract 1, glucose 5, KH2 PO4 0. 7, K2 HPO4 0. 5, MgSO4 · 7H2O 0.5,FeSO4 0.01 ,NaCl 0.5, microelement salt 1mg/L. After a 72-hour incubation with initial pH 7.0 at 30 ℃,the enzyme activity reaches to 35. 17 × 10^-10 mol/s, which is 1.59 times higher compared with the activity before optimization. The optimum chitinase producing temperature and pH of Bacillus subtilis 2-3-2 are pH 7.0 and 40℃ respectively. In an alkaline condition, if the temperature is above 40 ℃, the enzvme activitv is lowered