Menu
Processing of spent mushroom substrates to fibers using ultra-fine grinding and extrusion
- Renald George Swamy
- Spent mushroom substrate (SMS), a by-product of edible mushroom cultivation, is primarily composed of wood residues and lignocellulosic materials. This material has been explored for applications such as plant fertilizers, animal feed, and bioenergy production. SMS has also shown potential for fibrillation into nanoscale fibers through mechanical processes, typically with the aid of chemical pretreatments. However, this study aims to explore the fibrillation of SMS without any chemical pretreatment by utilizing two mechanical processes: ultra-fine grinding and co-rotating twin-screw extrusion. Fiber morphology was assessed using optical microscopy and scanning electron microscopy, while tensile testing and contact angle measurements evaluated the properties of the resulting sheets. The results indicated significant differences in fiber sizes after fibrillation wherein ultra-fine grinding produced finer fibers. The corresponding sheets from ultra-fine grinding exhibited similar mechanical properties in comparison to sheets from polylactic acid (PLA) and sheets with extruded fibers resulted in similar to birch kraft pulp papers. Moreover, an increase in hydrophobicity for the sheets from ultra-fine grinding was indicated due to the better network formation of smaller fibers. These results suggest that SMS can be effectively fibrillated into high-performance fibers without chemical pretreatment, presenting a valuable opportunity for transforming this by-product into sustainable packaging materials.
