| dc.description.abstract | The carboxylate platform is a biomass-to-energy process that converts biomass into hydrocarbon fuels or chemicals. The mixed-acid fermentation is the essential unit of the process that uses mixed cultures of microorganisms to anaerobically produce carboxylic acids; however, high acid concentrations in fermentation broth inhibit the microorganisms and negatively affect fermentation performance.
This study employed a weak-base anion-exchange resin (Amberlite IRA-67) to recover inhibitory acid products from countercurrent and propagated fixed-bed mixed-acid fermentations. The ion-exchange resins were employed in a novel fluidized bed that was purged with COv2. Compared with traditional plug-flow ion-exchange adsorption, fluidized-bed COv2-sustained ion-exchange resin adsorption increased carboxylic acids recoveries by up to a factor of 4.58 times.
Four countercurrent fermentation trains with an average 1.4 L total liquid volume were established under identical conditions. Different amounts of IRA-67 resin (10–40 g wet resinvFB) were employed to adsorb the acids produced from fermentation trains in the presence of COv2. The increases of biomass conversion and acid yield were found out to be 34–128% and 45–107%, respectively. The optimal normalized resin loading for biomass conversion was the 10.9 g wet resinvFB/ (Lvliq·d).
One train of propagated fixed-bed fermentation with 1.45 L total liquid volume was run under the same conditions as the countercurrent trains. With COv2, 30 g wet resinvFB was employed to adsorb the acids produced from this train, which caused acid yield to increase by 24%. | en |
