Abstract: The effects of culture condition on β-glucosidase preparation by Aspergillus niger in submerged fermentation and the apparent enzymatic properties of β-glucosidase were investigated. Wheat bran was the optimal inducer of β-glucosidase among tested carbon sources. The optimal culture condition of β-glucosidase preparation by A. niger in submerged fermentation was 40mL medium in 250mL shake flask, the inoculation was 8%, the initial pH value was 5.5, the culture temperature and rotation speed of Incubator Shaker were 30℃ and 170r/min, respectively, and the highest β-glucosidase activity of 19.12IU/mL was obtained for 10 days cultivation. The optimal temperature and pH value of β-glucosidase reaction was 65℃ and 4.8, respectively. The β-glucosidase was stable under 40℃ and in the environment pH value of 3.0-5.0.

Key words: Aspergillius niger, β-glucosidase, wheat bran