Bioconversion Efficiencies of Lignocellulosic Soy Stalk by Pleurotus eryngii Strains

The bioconversion of soy stalk (SS) lignocellulose by three different starins of Pleurotus eryngii from various origins by solid state fermentation was studied during 40 days. The effect of rice bran ratio, 5% or 10% (w/w), on lignin degradation and laccase activity were measured througout the fermentations while, total crude protein and C/N ratio of the remaining substrate were determined at the end of the fermentations. The degradation of lignocellulose was found by the determination of acid soluble lignin (Klason lignin) content. All the strains degraded lignin with different extents. The amount of lignin degradation was decreased by the addition of the higher quantities of rice bran (SS+10% RB). The highest lignin degradation was obtained as 24.43% by P eryngii var. ferulae (E) and the highest protein level was found to be %13.32 by P eryngii (H). We determined that the laccase activity was generally decreased by the addition of the higher quantities of rice bran (10%). Maximum laccase activity (204.39 U/L) was obtained by P. eryngii (E) on SS + 5% RB at the end of the fermentation. This study showed that, after fungal treatment soy stalk can be used as a feed for ruminants with its higher feeding value.