Abstract:
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, KH2PO4 0.7, K2HPO4 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 enzyme activity is lowered.
