Corn steep liquor is the essence of corn, which is rich in nutrition, especially rich in various amino acids, inorganic salts and vitamins. All of them are rare nutrients with low price and good quality for microbial fermentation. According to the different uses of users, some special requirements are often put forward. Therefore, the producers of corn steep liquor should adjust the process appropriately to meet the requirements of users.

(1)High protein content of corn steep liquor is needed

From the relevant data, it can be seen that there is almost a linear relationship between the content of dry matter protein and the content of lactic acid in corn steep liquor. The content of lactic acid is more than 12%, and the content of protein is more than 40%. If some test data show that the content of lactic acid is 12.51%, protein content is 44.37%; the content of lactic acid is 13.91%, protein content is 46.65%; the content of lactic acid is 18.74%, protein content is 47.80%.

The measures to increase the content of lactic acid in corn steep liquor are as follows: reducing the content of sulphite and temperature, prolonging the soaking time, persisting in countercurrent circulation, pouring a small amount of old corn steep liquor from quick release tank into newly added di2-3 tank when necessary, or adding lactic acid bacteria into the system.

(2)Low or high phosphorus content of corn pulp is needed

The phosphorus content in corn steep liquor is mainly related to corn varieties, and the phosphorus content is directly related to the ash content of corn itself. Generally, the phosphorus content in corn accounts for about 20% of the ash content, that is, the higher the ash content in corn, the higher the phosphorus content in corn, the lower the ash content in powdery corn, followed by Maya corn, and the higher the ash content in hard corn. The phosphorus content analysis of these three kinds of corn samples 35%, 1. 45% and 1. 61% (all dry basis) respectively. If the user has requirements on the phosphorus content of corn pulp, the appropriate corn varieties can be selected for impregnation to meet the user's requirements.

(3)If the process is considered, the contact time between corn steep liquor and corn, and the concentration of corn slurry can be considered. The phosphorus content of corn steep liquor with long contact time and high concentration is higher, on the contrary, it is lower. 20 h is almost the dividing line The corn kernels within 20 hours mainly absorb water, most of the phosphorus is still in the combined state, and the dissolution is less. The moisture of corn kernels is close to the balance above 20 hours, and the phosphorus of corn kernels is also dissolved in a large amount and transferred into the corn steep liquor. Therefore, if the corn steep liquor with high phosphorus content is needed, the dilute corn steep liquor with short contact time with corn can be used, that is, the dilute corn steep liquor with relatively low concentration can be evaporated and concentrated for standby, otherwise, the contact time with corn can be used In addition, the need to reduce the phosphorus content of corn steep liquor can also be taken to add a small amount of alkali appropriate neutralization, so that part of the phosphorus forms sediment, after clarification, take the upper clarified corn slurry to evaporate.