Alkali densification pretreatment of lignocellulose for improving the production of Pleurotus ostreatus

Pleurotus ostreatus is a mushroom characterized by rich nutrition and high protein content. It is abundant in essential nutrients for the human body and constitutes sustainable and functional food. The traditional cultivation materials (corn cobs, straw) for P. ostreatus are rich in lignocellulose. However, the stable structure of lignocellulose seriously hinders the utilization of these materials by P. ostreatus. In this study, we adopted acid/alkali densification and ammonization twin-screw extrusion and thread rolling (ATR), to pre-treat cultivation substrates before using them for the cultivation of P. ostreatus. The additional concentrations of acid and alkali reagents were initially investigated. The optimal concentrations were screened out as H₂SO₄ (5 %), Ca(OH)₂ (8 %), and NaOH (8 %). Through the analysis of the composition and microstructure of lignocellulose, it was discovered that these pretreatment methods could effectively disrupt the structure of lignocellulose without exerting any influence on its components. Further studies revealed that the pretreatment with 8 % Ca(OH)₂ was more favorable for the growth of P. ostreatus fruiting bodies. This approach increased the total yield of P. ostreatus by 28.30 %, enhanced the biological efficiency by 18.47 %, raised the dry weight by 24.32 %, and elevated the degradation rate of hemicellulose by 47.19 %. Meanwhile, the pretreatment of raw materials with ATR was more conducive to improving the nutritional value of P. ostreatus. This method increased the total amino acid content by 37.86 %, the crude polysaccharide content by 48.41 %, and the protein content by 40.67 %. This study offers novel insights into the innovative pretreatment approaches for traditional raw materials used in P. ostreatus cultivation.