(660h) Renewable Deep Eutectic Solvents (DES): Making Possible the Biochemical Conversion of Lignin

Colombia has a vast plantation of sugar cane and one of the highest sugar productivities of the world (Ton per hectare) what causes an annual production of more than 6.5 million tons of bagasse on the region. Sugar cane bagasse is approximately composed of 45,3 % cellulose, 27,5% hemicellulose and 23,6% lignin. However, lignin solubilization and extraction has been recognized by the scientific community as the main limitation for its efficient conversion. Existing methods cannot recover a large quantity of high-purity lignin without alterating its chemical structure.

This study reports a new method to extract and dissolve lignin from sugar cane bagasse produced in Valle del Cauca-Colombia region using a set of in-house synthesized Deep Eutectic Solvents (DES). The DES is a mixture of two or more chemicals acting as either hydrogen-bond donors (HBD) or hydrogen-bond acceptors (HBA), and it has been recently reported as a potential solvent for lignin extraction. We design the DESs to use only renewable materials that can be obtain from biomass. The resulting DES lignin has unique structural features with high potential towards a biocatalytic conversion approach. The efficient extraction of lignin and the increase of its reactivity towards biological conversion is due to the exposition of the new active sites for conversion, as lignin conformational changes from a rigid structure to a relaxed conformation during solubilization.

This study presents an opportunity to find a set of suitable conditions to facilitate extraction and solubilization of high purity lignin from sugar cane bagasse with high purity and minimal chemical modifications, which will help establish breakthrough pathways in lignin Biochemical valorization research.