Abstract:

To achieve the optimal fermentation conditions of the lactase-producing yeast Kluyveromyces lactis, the optimal cultural conditions were obtained using orthogonal design. The optimal seed medium compositions were as follows: glucose 2%, yeast extract 0.35%, peptone 0.35%. Meanwhile, the optimal compositions of fermentation medium were as follows: lactose 4%, glucose 2%, urea 0.15%, KH2PO4 1%, MgCl2 0.1%, MnCl2 0.01%. The cultural conditions were: inoculation size of 5%, at a temperature of 30℃, initial pH 7.0, shake flask rotation of 140 r/min and culture time of 18 h. Under these conditions, the lactase activity of K. lactis could reach 20.861 U/mL.