Using natural deep eutectic solvents for the extraction of polar and non-polar compounds from sugarcane waste generated in Brazil and Australia

Abstract

Sugarcane (Saccharum sp) is an important crop in Brazil and Australia, being the first and seventh biggest producers, respectively. To produce bioethanol and sugar, the amount of waste generated is 5 times bigger in mass than the major products. Straw, bagasse and filter cake are the main solid residues generated during the processing of sugarcane. They could be a source of high value-added compounds in a biorefinery concept. An extensive list of specialized metabolites has been reported for sugarcane residues, such as interesting lipophilic compounds (policosanols, known as cholesterol-lowing agents, for example) and medium to high polarity compounds (C-glycosylated flavonoids, for example, with antifungal activity). From an environmental perspective, there is no sense in converting agricultural wastes by employing polluting technologies, since that would increase the amount of wastes, which is the opposite of the desired outcome. Natural deep eutectic solvents (NADES), with potential use as green extraction media due to their bio properties appear as very promising alternatives. Their ability for extracting a wide range of polar to medium polarity secondary metabolites has been demonstrated and the use of hydrophobic NADES is under recent advances. Additionally, the reduction of the required energy and solvent consumption while fastening and improving extraction efficiency are main goals on green extractions. Microwave-assisted extraction and ultrasound-assisted extraction have been employed to intensify extraction of compounds from plants. The project aims to develop hydrophilic and hydrophobic NADES for extraction of both polar and non-polar secondary metabolites from sugarcane waste using green extraction techniques which could enable fast, efficient and green sample preparation. (AU)