Abstract: The high crude fiber content of corn husk produced by fermentation and starch and sugar industry was used as raw material, and the content of crude fiber in corn husk was reduced and the content of protein in fermentation products was increased by multi-strain solid state fermentation to prepare cell protein feed. Strains were selected for fermentation combinations according to the characteristics of substrates and product. And the effects of strain ratio, inoculation amount, fermentation method, molasses content and nitrogen source type on crude protein, crude fiber and true protein in fermentation products were investigated by single factor experimental design. The results showed that the optimum strain ratio of bacillus subtilis CGMCC 1.7417∶Bacillus subtilis CICC 10090∶Saccharomyces cerevisiae CICC 32236∶candida utilis CGMCC 2.2878 was 1∶1∶2∶2. The Inoculation amount of seed liquid was 15%. The best fermentation method was shallow plate fermentation. The optimum molasses content was 10°Brix. The best nitrogen source was ammonium sulfate. After multi-strain solid state fermentation, the crude protein content of product was 21.38% with an increase rate of 32.47%. The true protein content was 10.77% with an improvement rate of 50.42%. The crude fiber content was 17.78% with a reduction rate of 14.19%.

Key words: solid-state fermentation by multiple microorganisms, corn husk, crude protein, true protein, crude fiber