Optimization of Fermentation Conditions for Bacillus natto

The single-factor method and orthogonal experiment method were used to optimize the fermentation medium of Bacillus natto.The results showed that optimal medium is as follows: yeast extract with 5 g/L,peptone with 10 g/L, sucrose with 12 g/L and NaCl with 5 g/L.The optimal fermentation conditions are as follows: temperature was 30℃; initial pH was 7.0;inoculation amount was 3%;shaking speed was 200 r/min;fermentation time was 22 h.