(498e) Adsorption of Galacturonic Acid Onto Anion-Exchange Resins to Enhance the Enzymatic Hydrolysis in a Proposed Citrus Processing Waste Biorefinery

Citrus processing waste (CPW) is considered as a renewable feedstock for biorefining applications. The main structural polysaccharides of CPW as cellulosic biomass are cellulose and pectin. A proprietary technology for the integrated pretreatment and enzymatic hydrolysis steps is being developed to enhance the hydrolysis reaction rate, and increase the yield of fermentable sugars. Galacturonic acid is produced as monosaccharide during the enzymatic hydrolysis of pectin resulting from the synergistic action of pectinases, cellulases, and b-glucosidase. Issues related to the inhibition of enzymatic hydrolysis due to product and pH take place from the galacturonic acid production. Galacturonic acid cannot be fermented by traditional yeasts, and genetically modified microorganisms have to be utilized for its ethanol fermentation making this process more complicated and expensive. Then GA has to be separated from enzymatic hydrolysis liquor to avoid these process inhibitions, and be recovered for its utilization and conversion in value-added products. The aim of this research is the development of process for the separation of GA during the enzymatic hydrolysis of grapefruit processing waste (GPW) as model biomass. This process is being performed using anion-exchange resins for the adsorption of GA in batch and semi-continuous systems. Laboratory experiments for the adsorption and recovery of GA from pure solutions and pectin hydrolysis liquor have shown the potential for the application of this technology to enhance the enzymatic hydrolysis rate and the yield of fermentable sugars. Furthermore, this innovative process could alleviate the environmental and economical issues related to wastewater treatment resulting from the biorefining applications of GPW.