Ultrasound-assisted regeneration of ion exchange resins for efficient detoxification of lignocellulosic hydrolysate in biorefinery

Resin adsorption is an effective technology for the fermentable sugar slurry detoxification in lignocellulosic biorefinery, but with the great limitation of the loss of resin capacity from inhibitor contamination and the extensive use of acid and base solutions for their regeneration. In this study, we developed a green and practical method with ultrasound assisting the depletion of poisoned resins in a reusable low concentration sodium hydroxide solution. The process, optimized at 50 % (325 W) ultrasonic power for 30 min, recovered 70 % resin adsorption capacity, balancing regeneration efficiency with minimal physical damage. SEM and FT-IR analyses were used to investigate the surface and chemical changes, while regeneration kinetics were modeled using the Boyd diffusion model. The regenerated resins were evaluated through multiple adsorption-desorption cycles and fermentation of detoxified acidic corncob hydrolysate (ACH) for xylonic acid production using Gluconobacter oxydans. During three rounds of regeneration, the productivity of xylonic acid was maintained between 7.05 g/L/h and 8.77 g/L/h with 100 % yield, which was improved 25 %–55 % over ACH without resin detoxification. This approach not only enhances the economic feasibility of lignocellulosic hydrolysate detoxification but also advances the biotechnological production of high-value chemicals from lignocellulosic biomass.