earticle

영어

The button mushroom, Agaricus bisporus, is one of the major economical crops cultivated in Korea. This mushroom showed the 5th production to 11,493 M/T in 2014. 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-36 were the most dominant and had the highest enzyme activities. 16S rDNA sequencing analysis showed 99% similarity of CY-36 to Bacillus amyloliquefaciens. To define the optimum conditions for the mass production of CY-36, 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 5.0~8.0 and 30°C, respectively. The optimal culture medium for the growth was determined as follows: 2.0% dextrin, 1.0% yest extract, 0.5% NaNO3, 3 mM MgSO4, and 0.6% valine. Enzymatic activities of CMCase and PGase secreted by CY-36 were the most prominent and CMCase activity were optimal at 40°C and pH 7.0, and PGase activity were 50°C and pH 6.0. The activity of CMCase was rapidly decreased at more than 4°C and pH 5.0, and the activity of PGase was rapidly decreased at more than 30°C but didn’t affect as pH change. Accordingly, Bacillus amyloliquefaciens CY-36 was potentially useful on the fermentation stimulation and softening of rice straw in the process of fermentation for mushroom cultivation.