Assessment of changes in lignocellulosic compositions of substrates during the production cycle of elm oyster mushroom (Hypsizygus ulmarius)

The study focuses on determining the relationship between the degradation of lignocellulosic fractions of substrates used in Hypsizygus ulmarius cultivation and mushroom yield in order to present a wider range of data on the needs of the fungus. Moreover, the comparison of nutritional composition of mushroom carpophores among the substrates was performed.In the study, H. ulmarius was cultivated on bean straw (FS), corn silage (MS) and wheat straw (BS), poplar sawdust (KT), pine sawdust (ÇT) and spent mushroom substrate (AMK). The degradation process of lignocellulosic wastes was characterized during 90 days of cultivation period and the results were correlated by comparing the mycelial growth and yield. BS was the best substrate for H. ulmarius due to its shorter crop cycle (28 days), high yield and biological efficiency (BE%) (340.0 g/kg and 93.1%). Consumption of hemicellulose was observed predominantly, during the spawn running period of cultivation. The decrease in lignin level during H. ulmarius cultivation is significantly lower compared to hemicellulose and cellulose. Cellulose was degraded mainly during the fruiting period, and it was observed that high cellulose degradation during the fruiting stage are positively correlated with the yield and biological efficiency of H. ulmarius. The high lignin content of the substrate is a limiting factor for H ulmarius yield. The chemical analysis confirmed the decrease in pH, C:N ratio, lignocellulosic content and increase in electrolytic conductivity (EC), nitrogen and the ash content of substrates during cultivation of H. ulmarius. Moreover, the fruitbodies cultivated on different substrates displayed high contents of protein (%12.11–20.07), ash (%6.11–7.96), and carbohydrate (%69.31–79.96), a total phenolic content of 3.65-4,64 mg gallic acid equivalents (GAE) per g, and a low content of fat (%1,98-%2,89. The study revealed that different substrates used in the cultivation are effective in mushroom yield, quality and nutrient content of mushroom and the key factor dominating a successful H. ulmarius cultivation to be substrate having moderate amount of N and low lignin and high cellulose content. Key words: Elm oyster mushroom, mushroom yield, hemicellulose, selüloz, lignin