1. The fermentation method is to use sugar, ammonia, homoserine as the culture medium, and refine the fermentation of glutaminus to produce L-threonine.
Using glucose as raw material, we selected the feedback inhibition and repression in the synthesis of nutrient deficient and structural analogues, and reached the acid production rate of 18 g/L for L-threonine, 14 g/L for Corynebacterium glutamicum, and 14 g/L for Cybacillus mucilaginosum.
Glucose [Brevibacterium flavum, Corynebacterium glutamicum, Cybacterium mucosum, etc.] → L-threonine.
2. Use Micrococcus glutamicus or Bacillus brevis, Corynebacterium to ferment sugar, ammonia, homoserine, etc., and then refine them. The concentration in the fermentation liquid can reach 5~20g/L.
3. It is prepared from crotonic acid or glycine. The product can also be obtained from glucose or starch by fermentation and refining with Escherichia coli, Brevibacterium flavum, Bacillus glutamicum or Corynebacterium crenatum as strains.