Green Deep Eutectic Solvents for Microwave-Assisted Biomass Delignification and Valorisation

Abstract

Aiming to fulfil the sustainability criteria of future biorefineries, a novel biomass pretreatment combining natural deep eutectic solvents (NaDESs) and microwave (MW) technology was developed. Results showed that NaDESs have a high potential as green solvents for lignin fractionation/recovery and sugar release in the following enzymatic hydrolysis. A new class of lignin derived NaDESs (LigDESs) was also investigated, showing promising effects in wheat straw delignification. MW irradiation enabled a fast pretreatment under mild condition (120 °C, 30 min). To better understand the interaction of MW with these green solvents, the dielectric properties of NaDESs were investigated. Furthermore, a NaDES using the lignin recovered from biomass pretreatment as hydrogen bond donor was prepared, thus paving the way for a “closed-loop” biorefinery process.

Combining acid-based deep eutectic solvents and microwave irradiation for improved chestnut shell waste valorization

“…The combination of microwaves and acid-based DESs in delignification processes has been reported before. 49,50,58,82 Usually, a short irradiation time is combined with a rather high working temperature (>100 °C). It is worth noting that the same ChCl-oxalic acid dihydrate DES here used was proven to be effective in the delignification of poplar wood flour after a very short irradiation time (3 minutes) and at mild temperatures (80 °C), 58 thus in agreement with our findings.…”

Mechanochemical Applications of Reactive Extrusion from Organic Synthesis to Catalytic and Active Materials

“…The matrix was stored in a dry place until use. The wheat-straw consisted of 21.8% (w/w) total lignin and 8.5% (w/w) inorganic materials (ash) [61].…”

Lignin as a Natural Carrier for the Efficient Delivery of Bioactive Compounds: From Waste to Health

“…Furthermore, traditional methodologies are often time-consuming and employ toxic or dangerous organic solvents, meaning that it is important to use alternative methods for sustainable practice. Green methods include extractions using recyclable deep eutectic solvents and ionic liquids [ 31 ], electric fields, cavitation (acoustic and hydrodynamic cavitation) [ 28 ], subcritical and supercritical solvent conditions, enzymes, microwaves and green solvents [ 32 ], including eco-solvents such as glycerol and limonene and natural solvents (e.g., vegetable oils, bioethanol).…”