Abstract: Through multinomial regression, the effects of different concentrations of carbon source, nitrogen source and inorganic salts on β glucosidase production were studied. The optimum components of mediums consisted of bran 4.9%, (NH₄)2SO₄ 0.4%, KH₂PO₄ 0.29%, CaCl₂ 0.05%, MgSO₄·7H₂O0.04%, FeSO₄·7H₂O 5mg·L^-1, ZnCl 21.4mg·L^-1, and sodium oleate 0.2%. The fermentation conditions (including temperature, time, pH, aeration, and inoculation rate and pattern) were also optimized. Under the optimized conditions, the activity of β-glucosidase produced from Asp. niger was increased from 17U·ml^-1 to 21.3U·ml^-1.

Key words: Multinomial regression, Fermentation condition, β- glucosidase activity