The suitability of banana leaf residue as raw material for the production of high lignin content micro/nano fibers: From residue to value-added products

Each year the agri-food industry produces millions of tonnes of lignocellulosic residue, which could be valorized for its composition. Taking into account the economic cycle, this valorization is increasingly necessary and important. The Canary Islands’ banana (Musa acuminate var. Dwarf Cavenish) is an example of this. Its annual production is around 400,000 tons, which translates into 320,000–400,000 tons of banana leaf waste or residue. This residue can represent an important source of raw material for the production of value-added products, such as lignocellulosic micro/nanofibers (LCMNF) for different applications. However, when using a residue as raw material for value-added products, the maximum exploitation rate has to be achieved in terms of producing the minimum amount of sub-residue. In this sense, the present work aims to produce LCMNF from pulp made of banana leaf residue and to assess their reinforcement potential and production costs for the papermaking sector. For the first time, high-lignin content LCMNF will be produced with the same reinforcing capacity than CMNF prepared from woody and bleached pulp, using methodologies under the umbrella of bioeconomy, waste valorization and sustainable growth. The obtained results showed that the presence of high contents of lignin and hemicelluloses promotes the fibrillation, leading to LCMNF with the same reinforcing potential than those obtained from wood and oxidative methods. In addition, the obtained LCMNF had lower production costs that the aforementioned and presented higher yield in terms of raw material utilization. However, further research must be still developed on decreasing production costs thereof.