Reactive extrusion as a sustainable alternative for the processing and valorization of biomass components

Abstract

Various biomass components have attracted interest for their applications in biofuels, biochemicals, and sustainable materials. In biomass valorization, the development of green processes that provide high yield and purity of components at low cost is highly desired. In lignocellulosic biomasses, valuable components include cellulose, hemicellulose, lignin, tannins, etc. Other biomasses contain various desirable components, such as pectins, lipids, sugar, etc. Extrusion is considered a promising green process for effectively deconstructing biomasses into their components due to its high shear, continuous, and flexible operations. The process may also involve in situ reactions, known as reactive extrusion. Reactive extrusion is advantageous due to the effective combination of physical and chemical deconstruction phenomena. Its superior shear capabilities also allow for higher solid processing, reducing chemical use and its related costs. Through review of existing literature, the reactive extrusion process has been improved through the adjustment of various processing parameters and the application of other treatment methods. Newer research areas in biomass reactive extrusion processing specifically focus on the application of green solvents. However, challenges still exist regarding the industrial application of reactive extrusion due to a lack of energy and cost analysis. This review critically reviewed the use of reactive extrusion to deconstruct biomass and recover its components. The treatment of lignocellulosic biomass and the subsequent valorization of cellulose and lignin was emphasized.