From lignocellulosic biomass to nanolignin: Sustainable solutions for a greener future

The global energy crisis, aggravated by geopolitical tensions and rising fossil fuel prices, and the need to mitigate environmental impacts associated with fossil resources, has highlighted the urgent need for sustainable energy sources and bio-based materials. Lignocellulosic biomass, derived from dedicated energy crops, agricultural residues and forestry byproducts, offers a promising solution. Composed of cellulose, hemicellulose, and lignin, this biomass is abundant and renewable. However, despite lignin being the second most abundant natural polymer, it remains largely underutilized. Lignin’s complex aromatic structure presents significant potential for converting it into high-value chemicals, biofuels, and advanced materials, but its extraction and valorization from lignocellulosic biomass remain challenging. Efficient pretreatment methods, including chemical, physical, and biological approaches, are crucial to unlock lignin's full potential. Recent advancements in lignin research have led to the development of nanolignin, a nanoscale derivative that offers improved properties such as greater surface area and dispersibility. Nanolignin shows promise in various applications, including drug delivery, biosensing, food packaging, and tissue engineering, aligned with green chemistry principles. This review explores the process from different biomasses to nanolignin, focusing on the structural intricacies of lignocellulosic materials, the pretreatment strategies for lignin extraction, nanolignin preparation and characterization techniques, and the potential applications of nanolignin. It aims to clarify researchers about some valorization methods of lignocellulosic biomass, highlighting the factors which influence the effective valorization of this biomass. By highlighting current challenges and future prospects, this work aims to stimulate further research and innovation, providing sustainable answers to the global energy and environmental challenges. • Lignocellulosic biomass can be valued as a source of nanolignin. • More eco-friendly biomass pre-treatments for nanolignin production are being explored. • Nanolignin can be used for various types of applications and new added-value products. • Nanolignin is a biodegradable nanofiller that can serve as reinforcement to biocomposites.