Fermentation technology of probiotic strain D-1

In order to increase bacteria production and ratio of spore formation, experiments were conducted to obtain the best fermentation condition and media, and to determine the growth curve under the most favourable culture. The most favourable fermantation for strain D-1 was 30℃ in temperature, 6.5~6.8 in initial of media pH, 5% inoculum size, and 100 mL media per 500 mL flask in volume. Suitable culture medium was obtained through testing the single effect of medium elements on growth of D-1, including carbon sources, nitrogen sources, inorganic salt and growth factor.The optimal prescription for D-1 fermentation, as determined by orthogonal testing, was composed of 2% maize starch, 2.5% peptone, 0.8% NaH₂PO₄, 1.5% maize syrup, 0.05% MgSO₄ · 7H₂O and 0.1%MnSO₄(3.08%). To obtain the best inoculate and culture time, the growth curve of D-1 was determined under the most favourable medium and culture conditions. As determined from the growth curve, the best inoculate time should be 18~20 h, and culture time should be 26 h.