Solid state fermentation of lignocellulosics into animal feed with white rot fungi

The high content of polysaccharides in lignocellulosics, particularly cereal straws, is a potential source of dietary energy for ruminants. However, their nutritive value is limited because of the poor digestion of complex polysaccharide in the rumen. In order to increase the digestibility of lignocellulose, biological methods of delignification can be used. The principle of these methods is the splitting of the cellulose-lignin complex by extraction or decomposition of lignin. The main problem of biological upgrading of lignocelluloses into feed is to find suitable micro-organisms, with metabolic patterns different from those of the rumen flora and fauna and a cheap large scale process. Ideal micro-organisms for upgrading of lignocellulosics into animal feed should have a strong lignin metabolism, with a low degradation of cellulose and hemicellulose. In this review, principles of solid state fermentation and fungal activities on lignocelluloses are briefly summarized.