Unlocking the potential of oat straw: Efficient pretreatment methods for enhanced glucose production

The excellent physical and chemical properties of deep eutectic solvents, especially the ability of some of them to dissolve biomass, make them broadly applicable in biomass pretreatment. In this study, oat straw was pretreated with deep eutectic solvents composed of choline chloride and an acid (formic, lactic, or oxalic acid). The highest reducing sugar yield was obtained for the formic acid/choline chloride mixture. Using a pretreatment temperature of 110 °C, a reaction time of 2 h, and a solid-liquid ratio of 1:20, the reducing sugar yield obtained by cellulase hydrolysis was 23.5%, the degradation rate of cellulose reached 76.9%, and hemicellulose was completely degraded. The pretreated oat straw was then analyzed by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. The changes in its crystallinity and lignin content compared to the untreated specimen were determined. A preliminary mechanism for the pretreatment of oat straw with formic acid/choline chloride was revealed. The study could provide an opportunity to expand the application in biochemicals or biological feed processes.