Evaluation of Solid-State Fermentation by Ganoderma lucidum Using Soybean Curd Residue

The effects of fermentation conditions on the production of polysaccharides from Ganoderma lucidum using soybean curd residue (SCR) as a substrate were investigated. Based on the optimum conditions of solid-state fermentation, the fermentation time, the inoculum size, and the C/N ratio were optimized by response surface methodology. The optimal fermentation conditions for G. lucidum polysaccharide were determined to be the following: 14.53 % of the inoculum size, 10.49 of the C/N ratio, and 21.18 days incubation. The maximum polysaccharide yield of 48.14 +/- 1.47 mg/g was obtained in the verification experiment. Furthermore, treatment with 20 mu g/mL of G. lucidum polysaccharide from fermented SCR showed significant stimulation for the macrophage proliferation and higher nitric oxide production. Compared with the unfermented soybean curd residue, the total phenolic compounds increased fourfold, and various amino acids were increased significantly in the fermented soybean curd residue. Therefore, a nutritious functional food or food additives could be produced using fermented soybean curd residue.