Abstract: From north China to south China, 32 samples of various types of soil were collected and main ecological factors which might affect the distribution of protease-producing bacteria were studied. Through the study, 491 strains of bacteria were obtained and purified. All of them were systematically observed and their protease-producing activity were half-quantitatively examined. The probable high yielding strains were chosen out and cultured by shaking-flask liquid fermentation method and their protease activity was quantitatively measured. Based on the different protease activity and distribution of bacteria, the relationship between ecological condition and distribution of protease-producing bacteria was studied and following conclusion was obtained: the ecological distribution of protease-producing bacteria has some positive relation with the amounts of soil organic matter and nitrogen.

Key words: Protease, Ecological distribution, Enzyme activity