Preparation method of refined corn steep liquor and nitrogen-containing starch syrup for fermentation

The invention discloses a preparation method of refined corn steep liquor and nitrogen-containing starch syrup for fermentation. The method comprises the following steps of: removing impurities of primary corn pulps and determining parameters such as pH and the like and the alkali titration curve of the primary corn pulps subjected to impirty removal; neutralizing by using ammonium carbonate by then referring to the alkali titration curve of the corn pulps, controlling and neutralizing the pH value to 4.9-5.1 and precisely filtering; or regulating the pH value of the corn pulps to 4.9-5.3 by using calcium oxide or calcium hydroxide, sttanding and ageing for 3-5hr, performing solid-liquid separation by using a filter press, wherein filter cakes are used as fertilizer or used for extractingphytin, and the filtrate is precisely filtered; and sterilizing the precisely filtered clear corn pulps, and performing heating and stirring as well as mixing and blending on the sterilized corn pulps by using 1-20 and 99-80 parts of starch syrup or starch sugar product with a certain dry solid substance concentration by weight, thereby preparing the nitrogen starch syrup for fermentation. The method can be used for regulating the dry solid substance concentration of the blended nitrogen-containing starch syrup for fermentation to satisfy different shelf life requirements of users.