The successful transition to cleaner energy depends on the efficient use of renewable resources such as lignocellulosic biomass, that have the potential to meet the world's long-term energy demands. However, processing these biomasses is not trivial. The biomolecules present are often part of recalcitrant cell structures, and pre-treatment steps are necessary, aiming at the deconstruction of the structure and consequente increase in the accessibility of enzymes, which is used in subsequent processing steps. Among the various pre-treatments available for structural deconstruction, the physical method by ball milling stands out, which has attracted attention for its various benefits in the context of biorefineries. It is a greener, more versatile pretreatment that, for example, improves the efficiency of the enzymatic conversion of polysaccharides to monosaccharides in the context of second generation ethanol production. The deconstruction of the supramolecular structure of lignocellulose is promoted by the energy generated by mechanical forces during the milling process (LIU et al., 2019). The pre-treatment by grinding balls, in addition to reducing the particle size, promotes mechanochemical reactions, and induces a reduction in the crystallinity and degree of polymerization of cellulose (SHEN et al., 2020). In this communication, the effects of that pretreatment could be successfully monitored by solid state nuclear magnetic resonance spectroscopy (13C CPMAS NMR) through the areas of characteristic carbon signals of cellulose, hemicellulose and lignin.

LIU, H. et al. Mechanochemical deconstruction of lignocellulosic cell wall polymers with ball-milling. Bioresource Technology, v. 286, n. March, p. 121364, 2019.
SHEN, F. et al. Recent advances in mechanochemical production of chemicals and carbon materials from sustainable biomass resources. Renewable and Sustainable Energy Reviews, v. 130, n. 38, p. 109944, 2020.