Sustainable Strategies for Full Use of Miscanthus: Biodegradable Seedling Pots and Lignin-Based Fertilizers

Miscanthus (Panicum virgatum L.), a biomass material known for its rapid growth and high biomass yield, is considered a suitable resource for producing biobased materials. Nevertheless, the dense and complex structure of Miscanthus hinders its full utilization. In this study, alkaline sulfite pretreatment of Miscanthus was carried out to separate the cellulosic fiber fraction and sulfonated lignin. Then, the fiber fraction was used to prepare biobased seedling pots via the wet foaming technique, and the maximum compressive strength of the prepared seeding pot could reach 1317 kPa. The surface coating of the seeding pot with wood wax oil further improved its hydrophobicity and water resistance. Furthermore, the resulting seedling pot with good biodegradability can be used to replace the petroleum-based plastic seedling pot, which could reduce plastic pollution. In addition, the fractionated sulfonated lignin was directly utilized as a fertilizer, showcasing a 6% increase in root and stem height of cabbage and a 15% rise in biomass (dry weight), compared to the humic acid treatment group. Therefore, this work offers a promising and sustainable strategy for the comprehensive utilization of Miscanthus, which can also be a beneficial reference for the better use of other kinds of lignocellulosic biomass.