Introduction Corn steep liquor is brown liquid made from concentrated corn starch slurry, corn steep liquor is rich in soluble protein, a number of precursor substances, with about 40% to 50% solids. it is organic nitrogen sources for growth of micro-organisms with very common application, and it can promote antibiotic penicillin biosynthesis. The use of dry corn steep liquor: it is widely used in antibiotics industry (penicillin, erythromycin, gentamycin, adriamycin daguan, aureomycin, etc ) vitamin (vc, vb2, etc), amino acids (glutamate, lysine, phenylalanine, etc. ), enzymes (amylase, glucoamylase, etc) and other fermentation industries, and in bio-fermentation process used as nutrients supplements such as water-soluble vegetable protein and water-soluble vitamin.