Polysaccharides extraction from Ganoderma lucidum using a ternary deep eutectic solvents of choline chloride/guaiacol/lactic acid

Abstract

In this study, a purposefully formulated ternary deep eutectic solvents (DESs), consisting of choline chloride, guaiacol, and lactic acid in a molar ratio of 1:1:1, was synthesized for the extraction of polysaccharides from Ganoderma lucidum. The physicochemical properties of the synthesized DESs, including viscosity, density, pH, and hydrogen bonds, were comprehensively examined. Verification of the formation of the ternary DESs was accomplished through Fourier transform infrared and Nuclear magnetic resonance spectroscopies. Subsequently, response surface methodology was applied to optimize crucial parameters for polysaccharide extraction using DESs, resulting in a maximal extraction yield of 94.72 mg/g under the optimized conditions. Cyclic experiments demonstrated the commendable cyclic stability of the DESs, with a recovery rate exceeding 88 %. Furthermore, experiments on monosaccharide composition, molecular weight, and antioxidant activity of the isolated polysaccharides were conducted. Density functional theory was employed to gain insights into the molecular mechanism of polysaccharide extraction by DESs. The findings revealed a triple hydrogen bond interaction and a high binding energy (65.29 kcal/mol) between the DESs and glucose, highlighting their significant contribution to the high extraction effectiveness. This molecular-level understanding underscores the inherent superiority of DESs in the polysaccharide extraction processes, providing valuable insights for future applications in this field.