earticle

영어

This study examined changes in decomposition-related enzyme activity secreted by the microorganisms isolated from button mushroom composts. Among the isolated microorganisms, bacterial strains CY-24 were the most dominant and had the highest enzyme activities. 16S rDNA sequencing analysis showed 97% similarity of CY-24 to Bacillus licheniformis. To define the optimum conditions for the mass production of CY-24, we have investigated optimum culture conditions and effects of various nutrient source on the bacterial growth. The optimum initial pH and temperature were determined as pH 6.0 and 30°C, respectively. The optimal culture medium for the growth was determined as follows: 0.3% mannose, 1.5% yest extract, 0.8% (NH4)2HPO4, 2 mM MnSO4, and 0.5% asparatic acid. Enzymatic activities of CMCase and PGase secreted by CY-24 were the most prominent and CMCase activity were optimal at 50~60°C and pH 6.0, and PGase activity were 60°C and pH 6.0. The activity of CMCase was inhibited by metal ions including Ca+ and Cu+, while the activity of PGase didn’t affect. The activity of CMCase was rapidly decreased at more than 30°C and pH 7.0, and the activity of PGase didn’t affect as temperature change but was rapidly decreased at more than pH 5.0. Accordingly, This strain was potentially useful on the fermentation stimulation and softening of rice straw in the process of fermentation for mushroom cultivation.