Chemical- and Solvent-Free Mechanophysical Fractionation of Biomass Induced by Tribo-Electrostatic Charging: Separation of Proteins and Lignin

Rapeseed oil cakes are proteo-lignocellulosic residues obtained after oil extraction from rapeseed seed, featuring high protein, carbohydrates, phenolic compounds, and lignin contents. Most often used as an animal diet supplement, its fiber and phenolic part might be valorized for biofuels; biomolecules and biomaterial production proved its fractionation can be achieved without alteration of its nutritional qualities or generation of effluents and wastes. In this study, an innovative dry fractionation technology combining ultrafine miffing (UFM) and electrostatic separation (tES) has been developed for rapeseed oil cake fractionation into protein- and lignin-rich fractions. The physical features as well as the biochemical composition of the produced fraction have been assessed herein. Thanks to UFM tES technology, protein-rich fractions with 38.4% more proteins than in the initial material and lignocellulosic-rich fractions with 80.0% more fibers can be obtained without either external heating or using any additional solvent and catalysts. Boasting a low energy consumption, UFM tES technology compared to conventional methods seems to be suitable for converting oil cakes biomass into ready-to-use fractions for feeding and fiber and phenolic to green platforms molecules and biomaterials