3.9. Comparison of the MCE produced by B. subtilis Takahashi with commercial rennet Based on the study shown above, remarkable milk-clotting activity can be obtained when B. subtilis (natto) Takahashi was cultivated in a medium containing sucrose (50 g/L), NaCl (10 g/L), MgSO4•7H2O (0.5 g/L), NaH2PO4•2H2O (3 g/L) and NaHPO4•12H2O (3 g/L) at pH 6 and 37 ◦C with shaking at 175 rpm for 1 day. The highest MCA obtained was 685.7 SU/ml (without concentration of the broth), or 12,000 SU/g (with concentration of the broth). As shown in Table 5, the fact that the MCA and MCA/PA ratio of the crude enzyme obtained in this study are comparable with those of Pfizer microbial rennin and Mucor rennin has made this product a good choice for further studies and industrial exploitations.