Pretreatment of Loblolly Pine Tree Needles Using Deep Eutectic Solvents

Abstract

Deep eutectic solvents (DES) are new ‘green’ solvents that have a high potential for biomass processing because of their low cost, low toxicity, biodegradability, and easy recycling. When Loblolly pine trees are harvested, their branches with needles are typically left in brush piles and decompose very slowly. Exploring the effect of DES pretreatment on waste pine needles was the goal of the present work. Loblolly pine needles were treated with three types of DES to prepare the biomass for enzymatic hydrolysis to glucose, a subject not readily found in the literature. The resulting products were analyzed by Fourier transform infrared spectroscopy, fiber analysis, and high-performance liquid chromatography. Glucose yields after pretreatment and hydrolysis were found to be six times that for untreated biomass with two of the DES. Fiber analysis indicated removal of lignin, hemicellulose, and ash from the needle biomass. Enhanced glucose yield was due to removal of lignin and disruption of biomass structure during pretreatment, so that the pretreated biomass was rich in cellulosic content. Based on the results shown in this study, among the three types of DES, formic acid:choline chloride and acetic acid:choline chloride pretreatment had better potential for biomass pretreatment compared to lactic acid:choline chloride.

Recent Advances in Lignin Depolymerization Techniques: A Comparative Overview of Traditional and Greener Approaches

“…This technology does not require any hazardous materials [22]. Recently, ionic liquid (IL)-based and deep eutectic solvent (DES)-based depolymerization approaches have shown great promise for sustainable and more selective lignin depolymerization [23][24][25][26]. Careful selection of greener solvents and the addition of microwave-based techniques could enhance the efficacy of these methods [23][24][25][26].…”

eutXG: A Machine-Learning Model to Understand and Predict the Melting Point of Novel X-Bonded Deep Eutectic Solvents

“…Among the thousands of examples published, − DES featuring a melting point (MP) below room temperature are the most interesting as they have the potential to replace both traditional solvents and ionic liquids in room-temperature applications. Moreover, and as recently described by our group, the broad chemical diversity of the components has allowed researchers to make DESs with a broad range of chemical and physical properties, enabling unique applications in extractions, , reaction media, , sensors, , drug delivery, , mass conversion, , biology, , and environmental remediation. , Chemically speaking, DES are supported by a delicate interplay of intermolecular forces that include electrostatic interactions, hydrophobic interactions, van der Waals, , and (probably most importantly) hydrogen bonding. − While some reports suggest that some of the properties of DES can be modulated by the addition of water, − it is absolutely clear that many of those properties are determined by the balance of intermolecular interactions, which are (in turn) determined by the structure and functional groups of the components.…”